THE MOSQUITO .TS RELATION TO DISEASE AND ITS EXTERAMNATION ALVAh H. DOTY, AX.D. THE MOSQUITO While the antennae of the female have hair-like pro- cesses (see above), the antennae of the male con- sist of well marked and easily recognized plumes. The Mosquito: Female (Smith) THE MOSQUITO ITS RELATION TO DISEASE AND ITS EXTERMINATION BY ALVAH H. DOTY FORMERLY HEALTH OFFICER OF THE PORT OF NEW YORK ILLUSTRATED NEW YORK AND LONDON D. APPLETON AND COMPANY 1912 Copyright, 1912, by D. APPLETON AND COMPANY Published September, 1912 Printed in the United States of America PREFACE This book has been prepared with the hope that it may stimulate the work of mosquito extermina- tion, so urgently called for. I have endeavored to bring together, in a plain and practical way, such information regarding the mosquito and its extermination as will be useful to those who may be interested in this work. For the use of valuable and very accurate illus- trations, I desire to express my thanks to Dr. L. O. Howard, Entomologist, Department of Agri- culture, Washington, D. C., and to the New Jersey State Experiment Station. A. H. D. New York. CONTENTS CHAPTER PAGE I. General Considerations i II. Propagation 8 III. Identification of the Mosquito . . 23 IV. Breeding Places 32 V. Food 40 VI. Length of Life 42 VIL Distance which Mosquitoes Travel . 43 VIII. Hibernation 47 IX. Extermination of the Mosquito . 50 X. Remedies and Agents for the Pre- vention and Treatment of Mos- quito Bites 75 LIST OF ILLUSTRATIONS PAGE The Mosquito: Female (Smith). Frontispiece Manner in which the eggs of the Culex pun- gens, or common house mosquito, are de- posited (Howard) 9 Deposit of eggs of the Anopheles (Howard) . 9 Larva (Smith) 13 Usual position of larva in obtaining air (How- ard) 17 Position of Anopheles larva in obtaining air (Howard) 17 Pupa (Smith) 19 Culex pungens, or common house mosquito: Female (Howard) . . . .• . 25 Anopheles, or malarial mosquito: Female (Howard) 29 Stegomyia, or yellow fever mosquito: Female (Howard) 33 Culex sallicitans, Salt Water, Swamp or Striped Legged mosquito: Female (Howard) . . 37 THE MOSQUITO ITS RELATION TO DISEASE AND ITS EXTERMINATION CHAPTER I GENERAL CONSIDERATIONS There are two reasons why the mosquito should be exterminated. First: because it is a common and dangerous medium of infection; second: because its bite is ex- ceedingly annoying, and seriously inter- feres with the comfort of those who re- side in or visit districts infested with this insect; besides, the normal growth of population and land value in sections where mosquitoes propagate in large 1 THE MOSQUITO numbers, particularly along the Atlantic coast, are frequently affected by these conditions. During the early part of the last cen- tury the parasitic origin of infectious dis- eases was suggested, but the limited re- sources of bacteriology at that period, and other reasons rather discouraged the fur- ther investigation of this subject. About 1880 the great discoveries of Pasteur and Koch, respectively a French and German bacteriologist, gave to the world indisputable evidence of the germ origin of infectious diseases. These sa- vants also devised new and improved methods for microscopic work and the preparation of specimens for examina- tion. Not long afterward Dr. Laveran, a French army surgeon, on duty in Algeria, 2 GENERAL CONSIDERATIONS found in the blood of malarial patients the specific organism or cause of this disease. This led to a long and exhaustive investi- gation to determine the medium through which malaria is transmitted, and resulted in the discovery that the means of infec- tion is a variety of the mosquito known as the "Anopheles." For this, credit is due Dr. Manson and Dr. Ross of Eng- land, chiefly the latter, for it was largely through his experiments in India that this important knowledge was obtained. So far as we know at the present time there is no other medium of affection in malaria. Still further important evidence re- garding the danger from the mosquito soon followed. During the occupation of Cuba by the United States in 1900 a com- mission appointed by the President to in- vestigate the cause of yellow fever, and 3 THE MOSQUITO the means by which it is transmitted, sub- mitted in their report conclusive proof that yellow fever also is transmitted only by the mosquito, a variety known as the "Stegomyia." It may be added that the germ of this disease has not yet been identified. Thus it has been found that the mos- quito is responsible for the presence of two diseases which in the past, and even now in certain sections of the world, have caused great suffering and an enormous loss of life. Proof has also been secured that the mosquito is the medium of infec- tion in other diseases, and also that the Anopheles and the Stegomyia are not the only varieties of this insect that are agents of infection. After the important discovery of Man- son and Ross the study of the mosquito and 4 GENERAL CONSIDERATIONS the means by which it can be exterminated were soon under way, and since 1890 rapid strides have been made in this di- rection, the pioneers in this work being among those who live in civilized coun- tries where malaria and yellow fever are particularly prevalent. The most effec- tive and extensive work was first under- taken in Italy; where as a result of ma- laria the army was at times almost unfit for service, and there is but little doubt that these conditions were responsible for the beginning of the extensive emigration to this country, as many deaths were an- nually caused by this disease. Greece has also been a great sufferer in this direction, for at times one-third of its population has been affected. Furthermore, it is well known that the abandonment of the work on the Panama Canal, under de Lesseps, 5 THE MOSQUITO was due to the great prevalence of ma- larial fever, which could not be controlled. The work of mosquito extermination has caused a great change in these condi- tions and has been followed by the most brilliant successes, particularly in Cuba and in the Canal Zone, where the work has been carried on under the direction of the United States Government, and which has furnished conclusive evidence that the ex- termination of this insect has long since passed the experimental stage and can be successfully carried out if proper means are employed. In order to intelligently and success- fully carry out the work of extermination, there must be a practical knowledge of the propagation of the mosquito, its habits, etc.; fortunately, this information is now available. 6 GENERAL CONSIDERATIONS Although there are many varieties of the mosquito found throughout the world, as well as in the United States, it will be sufficient for the purpose of this book to describe them under two classes: First, the Inland variety, of which the "Stego- myia" and "Anopheles" are types, and, second, the Salt Water Swamp, Atlantic coast, or Striped Legged mosquito. CHAPTER II PROPAGATION OF THE MOSQUITO Mosquitoes propagate only in water. While the eggs of the Inland variety are laid immediately upon its surface, those of the Striped Legged mosquito are proba- bly first deposited on the soft ground of the swamp, although development does not begin until the eggs are floated out by the incoming water. Usually within twenty-four hours the eggs are hatched and the larvae drop into the water. This constitutes the second stage of develop- ment of the mosquito and usually lasts from five to ten days, when the larvae are transformed into pupae, the third stage of development; this is of short duration, 8 Fig. i.-Manner in which the Eggs of the Culex pungens, or Common House Mosquito, are Deposited (Howard) Fig. 2.-Deposit of Eggs of the Anopheles (Howard) Those of the Stegomyia, and some other varieties of the Inland Mosquito and also the Culex sollicitans are laid similar to these. PROPAGATION not more than two or three days, when at its termination the birth of the full- grown mosquito takes place, for this insect does not afterward increase in size. From the deposit of the eggs on the water until the release of the winged in- sects a period of from ten to fifteen days usually occurs, depending largely upon climatic condition. Eggs.-All mosquitoes do not deposit their eggs in the same manner, nor are they of the same shape or size. Those of the common Inland variety, or house mos- quito Culex pungens, are dropped in the form of a raft or float, the individual eggs being shaped very much like a banana, and held closely together with the large end down, from which portion after rupture the larvae reach the water (Fig. 11 THE MOSQUITO i). The deposit consists of three or four hundred eggs; therefore, it is not difficult to understand the rapidity with which this insect propagates. The eggs of the Anopheles, Stegomyia, and some other varieties of the Inland group, as well as the eggs of the Striped Legged mosquito, are deposited sepa- rately, and flat upon the water, are differ- ent in shape, and much less in number. A deposit of eggs of the Anopheles will illus- trate this (Fig. 2). Larv^.-These appear about 24 hours after the eggs are laid upon the water. At first they are so minute in size that they are usually unrecognized by the naked eye, unless specially sought after, although they may even in their early stage be detected by their movements in the water. They increase rapidly in size 12 Fig. 3.-Larva (Smith) PROPAGATION and when full grown are about one-third of an inch in length and about the size of a very large thread. The head of the larvae is particularly prominent. In mos- quito infested districts these little bodies are commonly known as "wigglers." Although there are some small differ- ences in the larvae of the various types of the mosquito, their appearance is practi- cally the same and needs no special de- scription (Fig. 3). The activity and habits of the larvae are very interesting. The phenomena may be studied by placing a glass of wa- ter containing larvae between the eyes and the light. They will then be seen moving about the water in a rapid and jerky way, principally in quest of food, which they secure largely from the organic matter in the water. 15 THE MOSQUITO Although larvae cannot live out of water, they must also have air, and if carefully watched will at intervals of about a minute be seen to rise to the sur- face of the water, above which they ex- tend their lower extremity containing the opening of the respiratory apparatus, through which they receive the air; there- fore, it may be said that the larvae breathe through their tail. Just at this point exceedingly important information is ob- tained, for those who are dealing with the extermination of this insect, for while the larvae in securing air are usually at right angles with the surface of the water, with their heads down (Fig. 4), an excep- tion occurs in the instance of the larvae of the Anopheles, which not only lie close to the surface but parallel to it (Fig. 5). As a matter of interest it may be stated 16 Fig. 4.-Usual Position of Larva in Obtaining Air (Howard) Fig. 5.-Position of Anopheles Larva in Obtaining Air (Howard) Fig. 6.-Pupa (Smith) PROPAGATION that the larvae of certain varieties of the mosquito are predatory. The Psorofora Ciliata, popularly known as the "gallinip- per," a giant mosquito, is one of them. These larvae preferably feed on those of smaller varieties, although if they are not present they will eat their own kind. After an interval of from five to ten days, depending on the variety of mos- quito, climatic conditions, etc., the larvae pass to the pupal stage. Pup^.-These (Fig. 6) may be recog- nized by an apparent enormous enlarge- ment of the head of the larvae, and have the appearance of an exaggerated com- ma; they will usually be seen lying close to the surface of the water. It is probable during this stage no nourishment is re- quired. After a period of about two days the pupae will be seen to rise above the 21 THE MOSQUITO surface of the water, where the envelope is broken, and the full-grown mosquito appears; it hesitates only for a short time, evidently to get its bearings and try its wings, then flies away. CHAPTER III IDENTIFICATION OF THE MOSQUITO INLAND MOSQUITO In this class three varieties will be re- ferred to: the common variety, Culex pungens (Fig. 7), found throughout the world, and the Anopheles, and Stegomyia. It is the Culex pungens which is usually found in the house and is chiefly respon- sible for the annoyance caused indoors, and is therefore known as the house mos- quito. It is of medium size, with rather a thin body, and in color ranging from a deep yellow to a dark brown. It has no distinctive feature, for it is practically of one color, having no marking or bands on 23 THE MOSQUITO the beak or feet. The palpi, or mouth feelers, are short in the female. This description will in a general way answer for many of the inland mosquitoes, although the Anopheles and Stegomyia need to be specially described. The Anopheles, or malarial mosquito (Fig. 8), is more slender, with longer legs and body; there are three points which serve to distinguish this mosquito from the rest. First, the wings are spotted or dappled with brown or black, which are well marked and constant. Second, the palpi, or mouth feelers, are about as long as the beak in both sexes. Third, when at rest the head of the Anopheles points be- tween the front legs, and the body, and is almost at right angles with the surface upon which it rests, whereas in other mos- quitoes the body at rest is parallel to the 24 Fig. 7.-Culex pungens or Common House Mosquito: Female (Howard) IDENTIFICATION surface. These characteristics of the Anopheles should be carefully remem- bered, for they are always present and serve to identify it. It will thus be seen that the Anopheles may be detected both as the larvae and as the winged insect. The Stegomyia or yellow fever mosquito (Fig. 9), which is found only in the southern section of the United States, has the enviable reputation of being known as the most attractive mosquito which has come under observation. It is a compara- tively small one, with pronounced and bril- liant silver stripes on its abdomen and thorax; the legs are also striped, although not so pronounced as in the case of the Salt Water Swamp mosquito; besides, it has no broad transverse stripe of white on its beak, which is found in the latter, 27 THE MOSQUITO It is also smaller in size than the salt wa- ter swamp mosquito. Both the Anopheles and Stegomyia are notoriously house mosquitoes, and are most vicious in the late afternoon, evening and probably very early in the morning. the culEx solliciTans, also known as THE salt WATER SWAMP, ATLANTIC COAST, OR striped legged MOSQUITO Although this variety is the chief source of annoyance along the Atlantic coast, it is not a house mosquito, and usually car- ries on its attack outside, although it may be brought into the house on the clothing, or otherwise. It is easily recognized without the aid of a glass by the broad white transverse band on the middle of 28 Fig. 8.-Anopheles, or Malarial Mosquito: Female (Howard) IDENTIFICATION its beak and also the distinct white bands on its legs (Fig. io). In order to become familiar with the different varieties of the mosquitoes re- ferred to in this book, the reader should carefully study the various parts of the mosquito referred to in the Frontispiece. CHAPTER IV BREEDING PLACES INLAND MOSQUITO This variety does not breed in salt water swamp land, but elsewhere it will propagate in almost any receptacle con- taining water. These are so numerous and so many of them unsuspected that they frequently escape detection, even on the part of those who are making diligent efforts to find them. About the premises they usually consist of old tin, crockery and glass ware, broken roof leaders, cess- pools, drains, unused water troughs, rain water barrels, cisterns, etc., unused recep- tacles about the barn and other outhouses. Urns in cemeteries, statuary in parks or 32 Fig. 9.-Stegomyia, or Yellow Fever Mosquito: Female (Howard) BREEDING PLACES elsewhere are also common breeding places; in fact, there is practically no limit to them. A very prolific means of propa- gation are found in excavations for new buildings, streets, sewers, etc., which are very frequently overlooked; besides there are innumerable places about manufacto- ries, public buildings, water tanks on apartments and tenement houses. If breeding places were always exposed, their detection would be much easier, but in many instances the receptacles are hid- den by long grass, weeds, and underbrush, which make their discovery very uncer- tain. Contrary to the general belief, mosqui- toes do not breed in large bodies of water, unless these are particularly rich in or- ganic matter, as in extensive collections of sewer water. They, however, breed 35 THE MOSQUITO along their edges in small depressions such as may be formed by the hoofs of animals that come to drink. While a few varieties of the inland mosquito, probably the Anopheles and Stegomyia, may prefer clearer water for breeding, the more common ones prefer that which is contaminated, containing a large amount of filth, not only to secure rich nourishment for themselves, but also for the future larvae; therefore, the dan- ger of filthy and stagnant water is ap- parent. Rain water barrels and cisterns found in the country are very prolific breeding places, so much so that the Culex pungens is sometimes referred to as the rain barrel mosquito. 36 Fig. io.-Culex sollicitans, Salt Water Swamp or Striped Legged Mosquito: Female (Howard) BREEDING PLACES culEx solucitans This variety breeds only in salt water swamps and not inland. Those who have not visited these swamps cannot appre- ciate the enormous breeding surface they supply. The surface of the swamps con- tains millions of depressions, and it is here that the eggs are deposited, the water being supplied by the incoming tide and rainfall. It is frequently asked why do not mos- quitoes appear in large numbers in certain sections where suitable places for breed- ing exist. This is probably explained by climatic conditions, insufficient or im- proper food, or some peculiarity of the place which does not encourage active breeding. CHAPTER V FOOD While mosquitoes are essentially vege- tarian, the females, the only ones which bite, crave blood, as those in mosquito in- fested districts will testify. The males do not take blood food. If a mosquito is carefully examined after biting, its abdo- men will be found enlarged, and if held before the light, a dark, opaque area will be observed representing the site of the meal. Whether or not it is necessary that the female shall draw blood before it is prepared to lay its eggs has been a subject of much discussion. While this form of nourishment is undoubtedly ad- vantageous, ovulation does not depend 40 FOOD upon it, for experimental work has shown that in receptacles containing larvae and protected by netting to prevent the escape of the new born mosquitoes, deposits of eggs have subsequently been found on the water; therefore, the latter must supply the sustenance necessary for this purpose. The larvae are voracious eaters and de- pend largely on the organic matter in the water, plants, etc., with which they come in contact. When they are removed from water rich in these products and trans- ferred to distilled water, for instance, which contains little or no organic mat- ter, they quickly die. The author has proven this many times by experiments. During the pupal stage, which is sim- ply preparatory to the birth of the winged insect, it is probable no nourishment is re- quired. CHAPTER VI LENGTH OF LIFE There is no truth in the belief that mos- quitoes live but a day, although it is very difficult to even approximately estimate their life cycle; however, careful investi- gation justifies the statement that the average life of an inland mosquito is about two or three weeks. The Ano- pheles, and the Stegomyia, of this group, and the Salt Water Swamp mosquito live somewhat longer, probably about a month. The above refers to the female, as the male lives only a few days. Mosquitoes have a definite function to perform-perpetuation of their species -which requires some time and occupies a large part of the period above referred to. 42 CHAPTER VII DISTANCE WHICH MOSQUITOES TRAVEL Perhaps no phase of the mosquito ques- tion has been so thoroughly discussed and so many various opinions expressed as the probable distance which mosquitoes go from their home, or breeding place. With- out reference to these various opinions, it may be said in a general way that the Inland variety is not a migratory mos- quito, and does not voluntarily go far from home, probably not more than a few hundred feet; however, it must not be for- gotten that they may be carried some dis- tance by winds or driven away by smoke, etc. Much practical proof has been pre- 43 THE MOSQUITO sented in confirmation of this statement; for instance, it has been found in yellow fever outbreaks, particularly in built up communities, and this is where the Ste- gomyia prefer to live and breed, that the secondary cases are first noticed in the ad- joining houses, or in houses opposite to where the original case occurred. These facts are also of interest in the extermina- tion of this variety of the insect, for if they are found in large numbers about the house, it may properly be assumed that breeding places are not far away. The Sollicitans, on the other hand, is a migratory insect and voluntarily goes far away from home; it may frequently be found miles from its breeding place, either inland or at sea. It is of great practical importance to know that the Salt Water Swamp mos- 44 DISTANCE THEY TRAVEL quito is a migratory insect, and that the inland variety is not. The sudden appearance of a large num- ber of mosquitoes calls for an investiga- tion as to the direction of the wind. This will oftentimes aid in the detection of breeding places. There is no doubt that mosquitoes are carried long distances by modern means of travel, and it will explain the appear- ance of these insects in sections hitherto free from them. Mosquitoes are particularly active at night; it is the time they breed and bite, usually during the early evening and about daybreak, although when enormous numbers are present, as in sections where the Salt Water Swamp mosquitoes propa- gate, apparently there is but little cessa- tion in their activity. 45 THE MOSQUITO During the daytime mosquitoes secrete themselves in long grass, underbrush, etc.; therefore, its removal in various ways adds to their destruction. The sudden appearance of large numbers of mosqui- toes after a rainfall suggests very strongly that they have been secreted in nearby foliage for protection, unless a strong wind is present. CHAPTER VIII HIBERNATION The perpetuation of the mosquito dur- ing the cold weather is a subject of great practical interest, although in tropical countries where there is more or less con- tinuous breeding it is not so important. A knowledge of the manner of hiberna- tion offers an opportunity to more com- pletely exterminate this insect by attack- ing it during its period of inactivity. Some very interesting information has been secured in this direction. We know that during the latter part of the fall some of the female mosquitoes of the in- land variety find their way to dark, warm and protected places, particularly cellars, etc., also occasionally the living portions 47 THE MOSQUITO of the house. Here they pass into the stage of hibernation, and in this dormant condition remain until the warm weather returns in the spring, when they again be- come active, seek a breeding place, deposit their eggs and die. It was formerly believed that all mos- quitoes hibernated in this way; now it is known that the Sollicitans hibernates in the form of the egg, instead of the winged insect. Late in the year the eggs are de- posited in the soft earth of the swamp, and remain there inactive until the spring with its increased temperature of the water leads to their development into the winged insect. Although larvae have been found alive during winter, they are probably not an important factor in the perpetuation of the mosquito, for it is positively known 48 HIBERNATION that the Inland variety hibernates in the form of the winged insect, and that the Sollicitans passes through this stage in the form of the egg. Almost everyone in mosquito infested districts has occasion- ally during the winter met with these in- sects when an apartment has been kept continuously warm or overheated; fur- thermore, investigators have been able in the spring to wash out and develop eggs removed from sods cut out of salt water swamps. The hibernation of the mosquito teaches us we may take effective measures dur- ing the winter to destroy the Inland va- riety and also to remove or destroy possi- ble breeding places early in the spring, for if none are available for the deposit of the first crop of eggs, there must be a great diminution or absence of the Inland mos- quito during the ensuing year. 49 CHAPTER IX EXTERMINATION OF THE MOSQUITO The extermination of the mosquito has long since passed the experimental stage, and successful results can be secured if proper measures are employed in carry- ing out this work. While individual energy and the interest which may be taken by a single community in this direc- tion is of value and should be applauded, it does not secure the general result which is desired, for this can only be obtained by an organization which includes under its direction practically the entire terri- tory involved. The treatment of a lim- ited area is practically of no avail where 50 EXTERMINATION the Salt Water Swamp mosquito is con- cerned, for the surrounding territory un- cared for will still furnish sufficient mos- quitoes for all purposes. The knowledge we now possess regard- ing the mosquito, its habits, life cycle, etc., and the positive results which have been obtained in its elimination, must remove all doubt as to its success. Those who undertake the work of mosquito exter- mination should feel this and persist until it is accomplished. Half-hearted efforts do not secure the desired results; further- more, the extermination of the mosquito should be in the hands of those who are practically familiar with this subject, or at least some one who has carefully stud- ied the literature connected with it. So far as possible, breeding places should be destroyed, and not treated. This 51 THE MOSQUITO is one of the cardinal principles of mos- quito extermination. Considerable has been written regard- ing the value of fishes, birds, etc., in the extermination of the mosquito. It is bet- ter that the consideration of this should be dismissed from the mind of those who are practically interested in this subject, for neither birds nor fishes can in any practical degree be depended upon for this purpose. It is as far from modern sani- tary methods as the reliance which in some countries has been placed upon the use of buzzards to remove garbage. It is true that in natural streams or collections of water certain fish devour larvae. While this undoubtedly diminishes the larvae present and in this way is valuable, it is impracticable to consider the development of either birds or fishes for this purpose, 52 EXTERMINATION and it should take no part in the efforts which are employed to get rid of this in- sect further than their use in fountains or other ornamental structures. As it has already been stated, there are two classes of this insect to be dealt with in the work of extermination, the Inland and the Salt Water Swamp mosquito. This must be fully understood in order to secure successful results, as each class re- quires the employment of different means of extermination, for their breeding places are distinct from each other. The extermination of the Inland mos- quito depends on the destruction or re- moval of all breeding places. This in- volves an exhaustive inspection to detect their presence, particularly those which are often concealed, and for this reason seriously militates against the success of 53 THE MOSQUITO this work, for the inland mosquito breeds in the most unsuspected places. Unless there is full appreciation of this, the de- sired results will not be obtained. It should be thoroughly borne in mind that the breeding places cannot be specifically enumerated, for any receptacle which will hold water may be used for this purpose. Many who are exceedingly careful in their examinations about the house will forget about the barn, out-houses, laun- dry, kitchen, etc., where may be found unused pails or other receptacles, which are prolific breeders. Water barrel and cistern, if they cannot be changed for more modern methods of collecting water, should be fitted with tight wire gauze covers, and should be frequently inspected and the water examined, for mosquitoes frequently gain access to these receptacles 54 EXTERMINATION through defects in construction, etc., and breeding may occur. Larvae are exceed- ingly sensitive, and the approach of a per- son to a rain-water barrel, for instance, will cause their immediate disappearance to the bottom or lower part of the recepta- cle; therefore, under these circumstances a dipper plunged into the barrel and brought up without larvae does not by any means prove they are not present. This must be repeatedly done with great care and patience, provided there is not suffi- cient light to detect them with the eye. In the country small pools and ground de- pressions are to be dealt with. As a rule, these cannot be drained, but if possible should be filled in; if this cannot be done, then the use of petroleum is called for. As already stated, mosquitoes - do not propagate in large bodies of water. They 55 THE MOSQUITO prefer small receptacles where there is quiet, rich nourishment and vegetation which afford protection. However, care- ful inspection must be made along their borders, for here in small depressions or holes may be found many breeding places. Cities and large towns are more free from mosquitoes than the country simply because in built-up sections there are fewer breeding places; still, in the city many breeding places are found. The various parks are breeders; so are water tanks on the roofs of buildings. The lat- ter are frequently overlooked because it is believed that mosquitoes do not fly suf- ficiently high. This is not the fact. There are many receptacles about factories, pub- lic buildings, etc., which should, but do not, receive careful inspection. 56 EXTERMINATION There is much connected with this work that comes directly under municipal con- trol which unfortunately receives little or no attention, such as cesspools, sewers and their connections, and more particularly new construction or repair work, which form many openings or depressions, used and unused receptacles for public use, etc., which are not often considered. Careful attention to this is very important in many ways and should call for prompt action on the part of municipal officers. It is not only a duty on their part, but is a public education, for it stimulates action in the same direction on the part of indi- vidual property owners. The use of petroleum oil must be re- garded as only a temporary measure, for it does not remove breeding places and deals only with the larvae which are pres- 57 THE MOSQUITO ent. Its application is therefore justifia- ble only when the breeding places cannot be removed or destroyed. Partly refined petroleum oil should be selected for this purpose, for the crude oil does not spread quickly or evenly over the surface of the water, and the refined oil is riot so effec- tive and is more expensive. Petroleum oil of the required kind may usually be purchased for three fifty to four dollars a barrel. The effect of this oil on the lar- vae is mechanical and destroys them, not by poisoning, as many believe, but by suf- focation. When the lower end or tail of the larvae is projected above the surface of the water for air it passes through the stratum of oil on the surface and the opening is closed or plugged and the respiratory ap- paratus rendered useless; the larvae die of suffocation within twenty minutes. Al- 58 EXTERMINATION though many agents have been suggested as substitutes, petroleum oil is the most practical and effective agent for this pur- pose. Experiments have shown that lar- vae will live for some time in compara- tively strong solutions of carbolic acid, corrosive sublimate, permanganate of potassium, etc. Besides, their use for the purpose of larvae destruction would in various ways be dangerous, particularly to animals who may come in contact with water mixed with these agents, while petroleum oil is cheap and harmless and can be depended upon to kill the larvae promptly. It should be applied about every ten days, in order to protect against new crops of larvae. A pint of oil for an estimated water space of twenty-five or thirty feet in diameter is a generous al- lowance. Although various forms of 59 THE MOSQUITO spray apparatus have been devised for its application, there is no more effective means of distributing it than by the com- mon garden sprinkling pot, with the holes in the expanded nozzle enlarged for the free exit of the oil. Rubber boots are a very necessary requisite for those who apply this agent. The inflammable character of the oil should not be forgotten, and the general supply should be carefully protected against danger. An important factor in the work of extermination, particularly in connection with the Inland mosquito, consists in the removal of tall grass, underbrush and other growths which generally harbor the mosquito during the daytime; this, how- ever, should be restricted rather to un- necessary growths, for it is hardly prac- 60 EXTERMINATION tical or proper to advocate the removal of flowers or other cultivated plants, which serve to beautify the premises, although so far as possible the principle should be carried out, for if there is no abiding place for the mosquitoes during the day- time many of them are destroyed. While extended cooperation and organ- ization are necessary to success in the ex- termination of the Inland mosquito, it is imperatively so when dealing with the Salt Water Swamp mosquito, for here the breeding places are often continuous for miles; therefore, the work of the indi- vidual owner is of little avail unless he controls the whole or greater portion of the swamp to be treated. There is but one way of exterminating the Salt Water Swamp mosquito, and that is by drainage. This has already been ex- 61 THE MOSQUITO tensively done and has furnished ample proof as to the success of the work. Salt water swamps consist of land which is constantly exposed to water regularly by tides and occasionally by rain. It is soft and spongy, and so water-soaked that there is but little escape for surface water, which is more or less constantly present, and furnishes places for the development of the larvae. Drainage allows of the prompt escape of the surface water by relieving the soaked or spongy ground, which is drained into the sea and is permitted to con- tract and to become harder and firmer, so much so that it can be driven over, while previous to ditching it is hardly able to support a man's weight. The re- moval of the water from the surface of the swamp kills the larvae, for experi- 62 EXTERMINATION merits have shown that they cannot be resuscitated if deprived of water even for a short time. This is aided by exposure to the sun, and indicates the value of removing or burning the various swamp growths. Experiments have also shown that a ditch properly dug draws water from sev- enty-five to one hundred feet on each side. This knowledge is valuable in deciding upon the distance which should intervene between the ditches. They should be deep enough to go below the strata involved, and wide enough to allow of free exit of their contents. The sides of the ditch should be straight up and down; in this way they are far more effective and the wash of the water tends to keep them in their original condition, or may even en- large them. A ditch, carefully construct- 63 THE MOSQUITO ed and kept clean, and well cared for, will remain intact for an indefinite period. Instances are reported where they have been operative for twenty or thirty years. The drainage work under the direction of the author on the Staten Island marshes consisted of the construction of ditches about two feet deep and ten to twelve inches wide, and at intervals of from one to three hundred feet, depend- ing upon the character of the swamp. In some instances it was necessary to dig them even closer together. They were made to discharge into larger ones, by which their contents could be carried to the sea. Natural creeks or waterways were utilized for this purpose, when they existed; otherwise, drains about four feet wide were constructed for this special purpose. 64 EXTERMINATION No system of drainage for the exter- mination of the mosquito will obtain suc- cessful results unless the ditches are kept clean and free from debris, which is prin- cipally brought in by the tide; otherwise they become clogged and form breeding places. The growth along their edges should be frequently removed, in order that the ditches may be freely exposed to the air and sun and more easily seen. It is far more effective and economical to continue the care of these ditches during the winter. The removal of the salt water hay or other growths found on the swamp is a valuable aid in exterminating the Sollici- tans, for it allows of greater exposure to the sun, which more rapidly dries the ground, and in this manner more prompt- ly destroys the larvae, particularly where 65 THE MOSQUITO ditches are in operation; it also takes away the protection which this growth gives to the winged insect, and in this way also aids in their destruction. It is hardly necessary to state that the use of petroleum oil is practically worth- less in the extermination of the swamp mosquito on account of the vastness of the breeding places and the need of the application of this agent about every ten days; besides, it offers no permanent re- sults in the extermination of the mosquito and would be detrimental in the prepara- tion of this land for agricultural purposes. The expense of draining swamp land depends largely on the character of the swamp, for in sections where more ditches are required the expense is relatively greater. A good workman after some experience will be able to ditch about 66 EXTERMINATION seventy-five to one hundred feet daily. These men can usually be secured for two dollars per day. Therefore, if the space between the ditches is decided upon, an approximate estimate of the expense can be made. It is generally understood that swamp land can be drained for about ten dollars per acre. Unless very long distances are to be dealt with, hand work is far preferable to ditching machines in many ways, for it is more economical and far less trouble- some. There is an important factor in connec- tion with the drainage of swamp land for the extermination of the mosquito which is commonly overlooked, i. e., its value as a preliminary step in the preparation of this land for agricultural or business pur- poses. Even without drainage, a growth 67 THE MOSQUITO occurs on the swamp known as salt water hay, which is in demand for packing and other purposes; this yields a profit of from six to ten dollars per ton. Under ordinary conditions it is very difficult to harvest it, owing to the spongy and uncer- tain condition of the ground, but after drainage the latter becomes firm and hard, and trucks may be driven over it, and the hay secured with but little difficulty. Therefore, drainage for the extermina- tion of the mosquito is a preliminary step toward the reclamation of the land for other valuable purposes. Under proper treatment this land is unequalled for rais- ing celery, onions, and other garden prod- uce. In the treatment of swamp land, either for the extermination of the mosquito or for agricultural or building purposes, 68 EXTERMINATION diking must in some instances be resorted to; this is perfectly feasible and practical, and is chiefly relied upon in Holland, where the ground yields the most valuable results. In the work of mosquito extermination frequent examinations should be made of the insects on the wing, in order that the varieties present may be known. Glass test tubes with light cotton plugs to pre- vent the escape of the mosquito should be left in various houses, with the request that as many as possible of these insects be captured, particularly at night, and placed in the test tubes. These should be promptly collected. Anopheles are often first detected in this way. Winter work in connection with the ex- termination of the mosquito consists in the inspection and care of the ditches in 69 THE MOSQUITO the swamp land, efforts to destroy the hibernating inland mosquito, and prepara- tion for active work in the spring. The means by which the hibernating mosquito is dealt with consists chiefly in the treatment of cellars, where it is known this variety commonly hibernates. Al- though a number of agents have been sug- gested for the destruction of the hibernat- ing mosquito, there is but one the author can recommend, i. e., sulphur dioxide gas, generated by burning common rolled sul- phur. This gas will destroy all insects and vermin with which it comes in con- tact. Unfortunately, it bleaches various fabrics, injures gilt and metal surfaces and damages various other articles, and for the above purpose its use is hardly justifiable throughout the house, although it is commonly employed in house disin- 70 EXTERMINATION fection where infectious diseases have oc- curred. In preparing the cellar for the use of this gas every opening must be closed and sealed, not only to secure its full effect, but to prevent its escape through the house; this may be done with strips of newspaper and ordinary flour paste. A method of generating sulphur diox- ide gas may be improvised as follows: Two or three bricks are laid on the bot- tom of an ordinary wash tub, upon which is placed a large sized tin pan, or some metal receptacle, for the sulphur. Water should be placed in the tub to a height just above the bricks and covering the bottom of the pan. This arrangement prevents danger from fire during the combustion which might occur if the pan containing the burning sulphur rested directly on the 71 THE MOSQUITO floor; it also protects the bottom of the pan. In order to secure so far as possible the complete combustion of the sulphur, it must be broken into small pieces, over which alcohol should be rather freely ap- plied methyl, or wood alcohol, which is quite cheap, will answer the purpose. It may be lighted preferably by a taper or by dropping a lighted match on the mass. This should be done while the operator is standing in order that the face may not be too close to the receptacle. When pre- pared in the manner above described, there is almost complete combustion of the sulphur. As soon as the sulphur is ignited the apartment should be promptly vacated and the exit tightly sealed and re- main closed for about *four hours, then opened and the gas allowed to escape. It must be remembered that the latter is not 72 EXTERMINATION respirable in the human being and is ex- tremely irritating to the respiratory tract and should be guardedly dealt with. Two pounds of sulphur should be burned for every thousand cubic feet of space in the apartment. If the cellar is large, two or three receptacles should be used in order to secure the better distribu- tion of the gas. It is sufficient if this treat- ment is carried out twice during the win- ter. In thus treating the cellar the care of the furnace, hot water apparatus, etc., must be considered, for they cannot be reached for a number of hours after the room is closed. The removal of groceries and articles of food which are uncanned or exposed should also be considered. It is questionable whether or not stables should be subjected to the use of this agent, although mosquitoes may hibernate 73 THE MOSQUITO in them. These buildings are, as a rule, not so tightly constructed as to prevent the escape of gas throughout the struc- ture; therefore, if horses or other live stock are present and it is not convenient to remove them they might be killed or seriously injured. The stable may also contain valuable harnesses, carriages and other equipment which are metal trimmed, etc., besides hay and other foodstuffs, which are exposed and may be affected by the gas. As the destruction of the hiber- nating mosquito depends so largely upon the interest and cooperation extended by house owners, it is probably best to con- fine this work to cellars until its value is more fully understood and accepted. CHAPTER X REMEDIES AND AGENTS FOR THE PRE- VENTION AND TREATMENT OF MOSQUITO BITES Undue consideration given to remedies or agents employed to relieve the discom- fort caused by mosquito bites, or to pro-1 tect against this annoyance, is to be de- plored, for it tends to obscure the impor- tance of exterminating this insect by de- stroying its breeding place, which is the logical and proper means of dealing with this condition. Innumerable remedies, however, have been suggested and em- ployed for this purpose, some of which are believed to give temporary relief. Almost any kind of smoke will drive 75 THE MOSQUITO away mosquitoes or will stifle them if they are subjected to it sufficiently long. In mosquito infested districts this has given rise to the practice of burning wood, leaves, etc., under the name of "smudge," which is often used with good effect by campers, although the mosquitoes appar- ently wait until the fire has subsided and then renew their activity with increased vigor. Pyrethrum, or Persian insect powder, is sometimes burned within the house to secure relief from mosquitoes which have found their way inside; however, in order to carry this out effectively it would be necessary to burn about a pound of this powder for every thousand cubic feet of space in the apartment to be treated. Just what real benefit would be derived from this is difficult to understand, par- 76 REMEDIES FOR BITES ticularly as fresh air is essential to com- fort and proper respiration. Various solutions or preparations are recommended for use about the sleeping apartment or to be applied to the skin to prevent the approach of the mosquito. Among them are spirits of camphor, oil of pennyroyal and oil of peppermint. The following is a favorite mixture:* Oil of citronella, I ounce Spirits of camphor, i Oil of cedar, % " To avoid the odor of the citronella in the above preparation, which is objected to by some, the following may be substi- tuted:* Castor oil, i ounce Alcohol, i Oil of lavender, I * Howard. 77 THE MOSQUITO It is said that the following mixture re- tards the evaporation of the oil of citron- ella in instances where its effects are desired:* Oil of citronella, I ounce Liquid vaseline, 4 A small amount of one of the above solutions or mixtures may be put on a towel and hung over the head of the bed, or applied to the face and hands; as they evaporate quickly, it may be necessary to repeat them during the night. The following remedies are commonly employed to relieve the discomfort caused by the bite of the mosquito. They are to be applied directly to the bite. When not in fluid form they are to be moistened: Ammonia, alcohol, glycerin, iodin, in- digo, soap, naphthalin, moth balls, also * Howard. 78 REMEDIES FOR BITES clean fresh earth. All of these agents have earnest admirers. The most reasonable and practical means one can employ to prevent the en- trance of mosquitoes within the house is the use of wire screens properly con- structed, and adjusted over all windows, doors and other openings. Curiously enough, even though this is understood, there are few houses where the screens are properly made or fit tightly over all openings, and there are spaces commonly present, and which, though small, allow these insects to enter. Neither are bed screens carefully selected or adjusted. If these conditions were carefully at- tended to the annoyance caused by the mosquito within doors would be reduced to the minimum. The: End A VOLUME FOR EMERGENCIES. A Manual of Instruction in the Principles of Prompt Aid to the Injured. Designed for Military and Civil Use. By Alvah H. Doty, M.D., Major and Surgeon, Ninth Regiment, N. G., N. Y., Attending Surgeon to Bellevue Hospital Medical Dispensary, New York. Fourth edition, revised to date. With 96 Illustra- tions. i2mo. Cloth, $1.50 net. This book is intended to impart the knowledge necessary for the prompt and intelligent care of persons suffering from hemorrhage, fractures, dislocations, wounds, contusions, burns, shock, sprains, poisoning, the effects of heat or cold, apoplexy, epilepsy, etc. It explains the proper treatment of those rescued from drowning, and other accidents which are liable to occur at any time, the results of which may be materially influenced by the care and attention which the sufferer receives at the outset. Each topic is explained in plain and simple language, and when medical terms are used their lay synonyms are also given. Of special interest to military organizations is the manner in which the matter has been arranged and points introduced that will be of use to the ambulance corps. The United States Army Drill Regulations for the Hospital Corps are given in complete form with profuse illustrations. In the new edition the chapter on disinfection has been entirely rewritten, in order to embody the results obtained by the latest scientific investigation. Those relating to wounds, hemorrhage, hygiene, poisons, etc., have been thoroughly revised. It is a work that should be in every home and office, and in the Company rooms of every military organization. D. APPLETON AND COMPANY, NEW YORK. "Heartily recommended to all who have to care for the sick."-Newark (N. J.) News. A Text-Book of Nursing. For the use of Training Schools, Families, and Private Students. Compiled by Clara S. Weeks-Shaw. Third Edition, revised and enlarged. With many Illustrations. I2mo. Cloth, $1.75. This book, first introduced to the public by Prof. Edward L. Youmans, to whose most kind encouragement and assistance it owed its existence, is now for the second time revised and brought up to date under the supervision of his niece, Dr. Alice C. Youmans. It follows the same practical lines as the earlier editions and, until something more com- prehensive is offered, it is hoped will continue to be of use to nurses both amateur and professional. ITS HIGH STANDING. " A valuable book."-New York American. "It covers the whole subject."-Philadelphia Prest. "Well written, practical, and authoritative." -Detroit Free Press. " It has the recommendations of the highest medical authorities." -Chicago Tribune. " Has long been known among nurses as the most reliable and comprehensive work of its kind." -New York Commercial Advertiser. D. APPLETON AND COMPANY, NEW YORK.