Malaria; and the Causation of 
Periodic Fever. 
BY 
BY HENRY B. BAKER, M-D., 
OF LANSING, MICH. ' 
Read in the Section on State Medicine, at the Thirty-ninth Annual 
Meeting of the American Medical Association, Cincinnati, 
May, 1888. 
Reprinted from the "Journal of the American Medical 
Association," November 10, 1888. 
CHICAGO : 
Printed at the Office of the Association, 
1888. MALARIA; AND THE CAUSATION OF 
PERIODIC FEVER. 
Reprinted from " The Journal of the American Medical 
Association," November io, 1888. 
Periodicity characterizes most and perhaps all 
physiological changes : The normal contraction 
and relaxation of muscles, and of protoplasm, 
the pulsation of the heart, the rhythmic respira- 
tory movements, the periodical sleep during the 
night, action and repose are the rule, and this ap- 
plies to thought and other nervous energy. 
Strongly-marked liberations of vital force occur 
only after a period of non-action has permitted 
the storing up of energy, which energy when 
once strongly and thoroughly discharged cannot 
immediately be followed by another similar dis- 
charge, for which time and opportunity for the 
accumulation of energy in dischargeable form is 
requisite. 
A periodic fever has, in the fact of its periodic- 
ity, a very strong indication that it is necessarily 
related to periodic changes in the patient, or in 
those environments of the patient which influ- 
ence physiological periodicity. Periodic fever is 
most frequently associated with those diurnal 
changes in the environment which are known to 
be associated with diurnal changes in human be- 
ings ; rest and sleep during the night, and action 
during the day, are the rule ; and periodic fevers 
usually recur daily or in multiples of days. 
The tension of the blood-vessels is in great 
part controlled by nerves which have been called 
vaso-motor nerves; and although these may not be£ 2 
controlled by the will, impressions on sensory 
nerves, and movements started by volition are capa- 
ble of influencing the vaso-motor nerves, and the 
calibre and tonicity of blood-vessels. In my opinion 
these facts have important relation to periodic 
fever, and especially to chills and fever; because, 
it is well known that chill and subsequent fever 
not infrequently follow impressions which are 
purely mental. A "nervous chill" thus caused 
has probably come under the notice of most ob- 
servant medical practitioners. The chill which 
not infrequently follows childbirth is also well- 
known, but has other factors than mental or 
volitional impressions, because involuntary mus- 
cular contractions also have occurred. 
The common phenomena of reaction from chill, 
if the chill is of considerable severity, include 
fever. In periodic fever-"fever and ague" 
(which term should be transposed, because the 
chill uniformly precedes the fever which is ap- 
parent) if the chill is accounted for, the fever 
seems to be explicable as the reaction from the 
chill, especially as the fever is comparatively 
ephemeral, it soon disappears, as it should do if 
reactionary only, and it only reappears after an- 
other chill; that is to say each recurring fever 
has the same cause, that cause being the chill. 
If this view of the case is correct, what has to be 
accounted for, then, is the chill, and its periodical 
recurrence. 
The time of day when the ague chill most fre- 
quently occurs, and the circumstances under 
which ' ' nervous chills ' ' occur, are facts which 
should aid our search for the essential conditions. 
I believe the ague chill is most frequent about 
noon, or not far from the warmest part of the day. 
My tables and diagrams show that there is also 
most intermittent fever in the warmest months of 
the year. It is generally conceded that there is 
most intermittent fever in the hot climates. 
High temperature of the atmosphere then, is the 3 
most important element in the causation of ague 
-intermittent fever. Whether the causation is 
direct or indirect is an interesting question. 
There are facts to be presented, further on in this 
paper, going to show that the influence of high 
temperature is, to some extent, indirect-through 
difference in the day and night temperatures. 
One alleged fact of this kind is that, in very 
malarious localities, exposure to the very high 
temperature on the low lands during the hottest 
part of the day does not cause the ague; but if 
one, thus exposed, remains on the low lands dur- 
ing the night, ague results, although the chill 
may not occur until the warmest part of the day. 
The great difference between the low lands and 
the high lands at night consists in the much 
lower temperature on the low lands.1 The cold 
experienced at night is much the greatest on the 
lowlands. If the night exposure to cold has 
causative relation to ague, how is it to be ex- 
plained ? Why is it that the ague chill is not co- 
incident with the chilling influence of the cool 
atmosphere ? 
Let us examine into the phenomena : 
The ague chill comes at a time later than the 
experience of cold. The "nervous" chill comes 
after the experience of the mental or other consti- 
tutional disturbance. The chill after childbirth 
follows the strong muscular contractions. The chill 
following surgical operations is after the cessation 
of the extreme muscular and nervous tension. 
The general fact seems to be that so long as the 
stimulus continues unabated and the organism 
unexhausted the nervous chill does not occur; 
but it occurs after the unusual tension has ceased, 
or after the nervous system is exhausted. The 
disturbed and irregular nervous control of the 
body in ague chill would seem analagous to the 
twanging of a violin string, the tension of which 
1 Experiments in Michigan, with registering thermometers, 
have proved that the difference is, frequently, great. 4 
has been lowered below its normal pitch. The 
vibrations are then irregular. 
I submit tables and diagrams showing the rela- 
tions of intermittent fever to atmospheric tempera- 
ture. 
It being apparent that whether or not there is a 
specific cause of ague, intermittent fever is a dis- 
turbance of the nervous system, and is, directly 
or indirectly, controlled by atmospheric tempera- 
ture, is there ready explanation of how at- 
mospheric temperature can control intermittent 
fever, irrespective of a specific cause ? 
But first those who think that a specific micro- 
organism is capable of causing periodic chill and 
fever may be allowed to show how it is possible 
for such specific cause to act periodically, or to 
induce periodic effects, or to cause fever or chills. 
It is alleged to be proved by Dr. Bernardo 
Schiavuzzi, in Istria, Austria, that the bacillus 
malaria, described by Drs. Klebs and Tommassi 
Crudeli, "is found in the atmosphere of malarial 
places, and more abundant the higher the tem- 
perature of the atmosphere and of the ground, 
and that corresponding to this the intensity of the 
malaria rose, meanwhile in the atmosphere of 
places free from fever this bacillus is not found.''2 
It is conceivable that this bacillus or some other 
may be inhaled, and that its products in the 
body may cause such an irritation or disturbance 
of the nervous system as we find in ague chill, 
and the periodical recurrence of the chill may be 
nearest the time of highest atmospheric tempera- 
ture, because at that time the bacillus is alleged 
to be most abundant in the atmosphere inhaled. 
But this is not in accordance with the alleged 
fact which seems to be well attested by numerous 
observers, that exposure in malarious localities in 
the daytime is not so frequently followed by 
2 " Concerning Malaria in general, and particularly in Istria." 
Wiener Medizinische Presse, 1887, No. 52, page 1779-80. 
Also letter, to the author of this paper, from Prof. Conrad 
Tommassi Crudeli, submitted to this meeting herewith. 5 
ague as exposure during the night. And, again, 
no one supposes that there is any bacillus or 
other microorganism concerned in the causation 
of nervous chill from mental or emotional dis- 
turbance, or of surgical chill, or of the chill 
following childbirth. These last-mentioned chills 
do not recur, but alternations of heat and cold 
day and night do recur, and tables of statistics 
which I have examined seem to prove that they 
are greatest in "malarious" regions, and slight in 
non-malarious regions, they are great in months 
preceding or when intermittent fever most occurs, 
and they are slight in months preceding or when 
that disease least occurs; and it would seem that 
in such periodical alternations of atmospheric 
temperature we must find sufficient cause for the 
production and for the periodic recurrence of ague. 
HOW ATMOSPHERIC TEMPERATURE CHANGE MAY 
CAUSE "CHILE." 
When a person is long exposed to cool night 
air, the abstraction of heat from the body is great, 
the demand for the production of heat is great. 
The impress on the nervous system is strong. If 
one thus exposed is awake and observant, the 
sensations will be remembered as peculiar as well 
as unpleasant. If the air is not cold enough to 
induce immediate reaction, there is a gradually 
increasing nervous tension until, if the exposure 
is long enough, shivering occurs, that is, the 
normally equable nervous control of the muscular 
system is disturbed. If the nervous system is 
well-nourished, and the exposure is not extreme, 
the reactionary relaxation of the superficial blood- 
vessels, which generally occurs on the subsequent 
exposure to warmth, is not great, especially if 
the warmth is applied to the extremities of the 
body. 
Under some circumstances, the nervous tension, 
due to an exposure to an atmosphere cold com- 
pared with what has recently been experienced, 6 
does not soon reach that stage where shivering 
occurs. Perhaps the shivering occurs soonest 
when the sensation of the chill is more local than 
general, and the most intense nervous tension 
without shivering is caused in those cases where 
the attention has been least called to the nervous 
disturbance, because the impress of the cold has 
been most gradual as well as general.8 
Given, a case of intense nervous tonicity (due 
to impress of a cool atmosphere during the night) 
and consequent clonic contraction of the involun- 
tary muscular tissue of the integument, what 
may occur on the experience of the day atmos- 
phere, in warm weather ? If the strong contrac- 
tions on the surfaces of the body continue, and 
the production of heat goes on at the same rate, 
the heat-loss will be greatly lessened, and this 
will be beneficial so long as the temperature of 
the body remains not above the normal; but if 
after a time the temperature of the air inhaled 
becomes much warmer, the heat-loss through 
respiration is, consequently, much less, the in- 
ternal body temperature may then become ab- 
normally high, as is the case, I believe, in the 
cold stage of ague. The abnormally high in- 
ternal temperature and the disturbed nervous 
control cause irregular muscular contractions, and 
the other subjective and objective phenomena of 
the chill; and, as is well known, these disturb- 
ances may be intensified on exposing the back of 
a person in this condition to the sun. The high 
temperature is caused (as I believe) by the con- 
tinued tonicity of the muscular system of the in- 
tegument, which does so much to regulate the 
heat-loss of the body, and which, under the cir- 
cumstances I have described, has been greatly 
stimulated in such a gradual manner that imme- 
diate reaction did not occur; but when the reac- 
tion does finally occur, it is excessive and ex- 
hibits that heat of the surface which is recog- 
3 See diagram and text relative to conditions in India. 7 
nized, by even non-professional persons, as 
' ' fever. ' ' The relaxation of the surfaces, brought 
about by this reaction, then proceeds until its 
maximum is reached in the sweating stage. 
Thus we have, according to my view, a clear 
grasp of the manner in which a first paroxysm of 
ague is caused by exposure to changes in atmos- 
pheric temperature. Given such alternations in 
atmospheric temperature as will cause a first 
paroxysm of ague, the chances are greatly in 
favor of there being similar alternations on the 
day succeeding, or, if not on that day, in a day 
or two afterwards, especially if it chances to be 
at that season of the year when the difference be- 
tween the day and night temperature tends to 
continue uniform ; and the repetition of those 
conditions which caused the first paroxysm 
should cause a second, and a third, and so on 
continually so long as the cause is repeated until 
death, or until the nervous system, which controls 
the surfaces, gains such sensitiveness to those in- 
sidious changes in the atmospheric temperature 
that normal or appropriate reaction promptly oc- 
curs on the experience of exposure to such in- 
sidious changes. 
This view explains why it is that quinine, 
strychnine, and those agents which have such in- 
fluence on the tonicity of the muscles, voluntary 
and involuntary, especially those which like 
quinine, have strong influence on the involuntary 
muscular system, have such influence over ague. 
Strychnine, as is well-known, renders the nervous 
system particularly sensitive to external impres- 
sions ; but its effects, in medicinal doses, are per- 
haps not so lasting as are those of quinine. 
It is a common observation that persons who 
travel northward, or to a colder climate, where 
ague is comparatively rare, not infrequently have 
one or more paroxysms of chills and fever soon 
after the change.4 The common explanation is 
4 During the late war, I noticed this on a large scale after move- 
ments of troops from the South. 8 
that they brought the disease with them in their 
systems. But this is not philosophic, because so 
long as they were at the South, to the tempera- 
ture changes of which locality they were accli- 
mated, they had no ague. The true explanation 
is that they were not acclimated to the tempera- 
ture changes in the cooler region; the contrac- 
tions of the surfaces, due to the tonic effects of 
the cooler climate, did not readily permit of the 
loss of any unusual body heat, such as would re- 
sult from muscular exertions; the nervous centres 
suffered, and chill and fever resulted. 
That persons not acclimated to a warm climate 
suffer from ague, is a still more well-known fact. 
It seems difficult to account for this by any other 
theory than the one which I am advocating; and 
by this theory it seems perfectly plain, because, 
in warm climates the daily fluctuations of tem- 
perature are so much greater than they are in 
temperate or cool climates; the demands upon 
the heat-regulating nervous system are therefore 
correspondingly greater. 
BLOOD CHANGES IN AGUE. 
The evidence relative to the excessive forma- 
tion of pigment by disintegration of the red blood- 
corpuscles, through internal congestions and the 
greatly varying constitution of the blood serum 
as regards water and salts, because of the exces- 
sive thirst and perspiration in ague, seems to have 
been omitted from this paper; but this reference 
to it may serve to suggest that, in the opinion of 
the writer, the evidence is in harmony with the 
other portions of this paper. 
DAILY RANGE OF ATMOSPHERIC TEMPERATURE 
DETERMINES INTERMITTENT FEVER. 
From time to time I have published3 evidence 
tending to prove that the prevalence of intermit- 
tent fever throughout the world is in proportion 
5 Reports of Michigan State Board of Health, especially for that 
of 1880, p. 318. 9 
to the difference between the day and night tem- 
perature-the average daily range of temperature 
to which people are exposed.6 
With this paper I submit tables and diagrams 
proving, as I think, that so far as relates to cer- 
tain parts of the world, this general law is correct. 
It is true in Michigan. It is true of that part of 
this country occupied by the U. S. Armies during 
the late war of 1861-5. The tables and diagrams 
sustaining this last statement include a study of 
the months of occurrence of over half a million cases 
(542,009) of intermittent fever, a number so vast 
that even though only three years' time is covered 
there is extremely great probability that true aver- 
ages have been reached. If you will study the dia- 
gram (No. 1.) you will see that the curve repre- 
senting the cases of intermittent fever follows with 
great uniformity the curve for average daily range 
of atmospheric temperature. It follows it in such 
a manner as to demonstrate, I think, that there is 
a necessary relation; and taken in connection with 
what we know of the regulation of body temper- 
ature by nerves which are in necessary relation to, 
and which normally respond to changes in the 
atmospheric temperature, the diagram seems to 
demonstrate a relation of cause and effect between 
daily range of temperature and intermittent fever. 
By the diagram it will be seen that so long as 
the daily range is increasing the number of cases 
under observation accumulate, perhaps because 
6 " It may be well to bear in mind in relation to this subject that 
intermittent fever is a disease of the warm season in this State, that 
it becomes more and more prevalent as we go south until in the 
extreme Southern States it is extremely common and severe, that 
the daily range of temperature is greatest in the warm months in 
this State, that it is greater in the warmer climates of the Southern 
States, that this is especially true on the lowlands, and that it is 
exposure during the day and during the night on the lowlands in 
the South which is believed to be so uniformly productive of chills 
and fever. 
"If periodic chills and fever is produced or greatly favored by 
excessive periodic changes in the temperature of the atmosphere, 
then the reason is supplied why exposure on the hot lowlands dur- 
ing the day and return to the warm highlands at night is not so pro- 
ductive of ague as is exposure to the cold night-air of the lowlands." 
Page 318, Rep. Mich State Board of Health, 1880. dto.l.dange of Jitmosphe r c e Jempe nature , and Jnt er nd lie nt 
J^uer thickness) in the btml&dStates JJrmies. 
j^W COJdt pvr Alton tk 
pc f/QjMO'S&l dieAs. 
By months, fail made Jo days) for a period of 3 
years, Ik'bZ-bV-, the relation tufa id the number of 
cases f Jiehness from Sylermiftentd^efor perWdl>mean, 
strength of the White Jr oops of the li.S. Armies infhe war 
of the re hellion^ustains to the Jh/erage daily Hange fM- 
trospheri cJemperataref)Me /ramber of cases representeclisSf^llDf I 
Degrees 'Jahr. 
-Jan, 
-Veb 
Star, 
dfr. 
Jun, 
Jut 
Hug. 
S^t. 
Ost. 
Joe. 
pec.,, 
(Sickness -. aAverage daily Range of dentpe nature........... 
*J7e sickness is comp il ed fromUeSHedieal and Sur gi cal History 
of the War of the Rebellion. Jhe range of Jemperature is compiled from, 
a table on page UH of the Smithsonian fables fisfribution and l/arlafion. 
ofthed/tmosphericJenip.inlhelb.Sfdtis for aperio dof R years, 
7^62-6^ afWatral Ooservafory Washington, D. C. dfo. Range of dUmospheric demperature, and drrfer- 
mittent j'ever Cdicknes) in jUtekijan, • 1 
Per cent of 
He par t s* 
J?t/ months, for a period of & t/ears, 
the relation of Sickness from 3nterm i tie nt 
fever in Mtfchigan fo th e Jtverrrge Jhaity 
Hanae of fernperatuLe e at groups f Stations, 
and at Lansing, drlich igaru. 
^Degrees fafr. 
Jan 
- Peb 
Mmr. 
jfr 
-Mag 
Jun. 
A Aug. 
j 
We/>t. 
Oct 
-J/ott. 
_ z>«c. 
Sickness----Average daily Range oftemperature.... 
three age daily Range of temperature at Lansing - - -- 
* indicating urhat per eent of all reports received staled, 
the presence of intermittent fever then under the observation, 
oftne physicians reporting. 
Oyer 3SOOO weekly reports of sickness, are re pre sent eel m 
this diagram. UTTl dtirnospkeric temperature and, 
inter m i tie nt' Joea er (S ickne ss) in Jdi c h i gam. 
By tnovtlhs, for a. period of f years, 1^7^~ Kb, 
the relation oj Sickness from 9htermiltent 
feuer tn Michigan lo the Average of the Baily 
dlCaximarri femperatare at Zansing Michigan. 
Per cent of 
Reports.* 
\9e greet fa hr. 
• Ja n. 
■ Peb. 
-Plinf 
- Map 
- </« n 
.Jul 
■ ^<y. 
-Oct 
-Mur. ' 
Rec. 
JickJtuerage max imum Jemperature - - 
^indicating u/kai per cent of all reports re ceiued,stated 
the presence of intermittent Jeuer then under the observation, 
of the physicians reporting. 
OneritfaoOdeehly reports of sichness are represented in this 
diagram.. ffo-lf*- Atmospheric temperature, and flange of Jemf., and inter- 
mittent fe ver(Siekness), Jlfemphis, Jkn.ro ■ 
C cues perJtontkS 
Uy months, (all wadi 30 clays) for a period of 3 years, 
IX8S-X7, the relation of Richness from Ante rrn it tent 
fe ver. in the 'Uj.S.Marine Hospital, atj/temphls, Jenn., 
to the -Average Jlinoospheric Jemperatu re^ and JI ver- 
age daily Han get of .fe mpe r al ar'e . (Jhe number 
ef cases represente d is S3!.) 
^Degrees fahr. 
- Jan' 
- Pel. 
-/far. 
Arr 
.May, 
-Jan. 
July, 
■dag 
. Sept. 
-Oet 
■ Vou 
Sec. 
Sickness ofioerage Atmospheric temperature . 
Jive-fage. daily flange of Je nij>eratu.re 
formal Jvr ISyearsjifl-HSfjormalfor Syearst f/-%S Jfo.S.-rttm ospkeri c Jentp.eraiure, and Hange of Jemp., 
and. intermittent fever (Sickness) C in C innati, Ohio. 
Cases per Month.. 
Sy months,(all made So days) for a period of y years, Itfif-tf 
the relation of Sickness from 9nt ermittent Jeu er in the 
Cincinnati Hospital, Cin., Ohio to the flue rage Jitmos- 
pherie Temper atu re, and Ju e rage Hal ly Kanye of 
Jemperature, ((The number of Cases represented is 
\iDegreej Fahr. 
■ San. 
Teh. 
Mar. 
Apr. 
May. 
Jan. 
Jul. 
Jag. 
Sept. 
Oct. 
■Has. 
■Jet'. 
Sickness .Average JHmospherie Jernperature _ . 
.Average daily Hany e of fe~mperature ................ • ^do. 6.-dttmaspheric .Temperature and Mange of aemy. and in- 
termittent feuer f SicknessJ San f-rane.sco, Cat. 
Cases perMoni/b\ 
by months, fall made 30 days) for a period of 6 years, 
/froMS, the relation -of Sickness from fnlerrnittent 
fever in the Citg and County Hospital, fan Jrancis co, 
Cal, to the Muergqe Mtmospherjc Je.mp e rat are and 
M) uera-ge Daily hanqe^of Je m p er at lir e- (Jbe number 
of cases represented is 37%) 
\ Degrees fa Ar. 
dan 
Feb. 
Mai". 
Apr 
•May 
Jun 
. Jul 
■^3 
i ye ft 
■Oet 
-Mod 
- pets. 
Sic^ness. Average ddmaspheric Temperature 
Jluerage daily Kange of Temperature 
rCTorm al for S yearj /rfl-xT. JVb.f dimospieric Jemperafure and 'Range of Jemp ancf .Ma- 
laricd dei/ers (Deaths) in JTeui &or& City, 
^Deaths jterMonth,. 
Sy months,(all made 30 days)for a p erip d of 2oyears, 
tff>X~f7r lite re lai ion of De ad Its from Malarial 
devers (remittent, intermittent, iypho~ malarial, 
congestive chills, pernicious fever), to the MeO- 
aqe dltmospheric uempe rature^and Average 
doillj Range^of femperature, in Hew l/orh City, (die 
number of deaths represented is 6, K ! S'), 
Deg-rees J?a hr. 
. Jan. 
rd. 
- MaO. 
■Apr 
■May. 
Jan. 
Jul. ' 
Ooi. 
Dec._ 
Derr.)As . Jfoerage Mmospheric. Jempera-lure _ _. 
pierage daily Range of .Temperature 
Tfbrmatfor /i/ years ftyods /fima/for S years, /TS'/S'S'. J(o ?. - Jltmospkeric Jempera-iure and, Hange of JJempera.tu.re 
and alar lai J)isease(J)eatlis) in tie State of Jfe u/ 1/orfc . 
^eath j fe rMo ntk. 
Dy monthsfallmade JO days)Jvr a period of 3 years, 
RZSidi'f the relation of Deaths from Malar tai Disease 
in the State of JCem d'ork.fo the Duer age Mtmospkerie ferrrn~ 
erature ^andMenage Daily hange^of Demperaiure. (Jhe 
number of deaths represented is 2,7/F./ 
Degrees fakr. 
• Jan. 
Veh 
Mar- 
Apr 
Muy. 
Jun. 
Jul. 
^3- 
•Sept, ■ 
Oat 
Mo a. 
Dec. 
Tipnfix . flu erage Jltrriospheric Semper aiure_ _. 
Jjuerage daily Hange of JJemperaiure 
^■formalfor /Jyear.S'/'ip/.'iS. iJforrnal for 5~years/%%JUS'S j^o.^.-yttmosphefic fempeoature anol flange of fem planet 
Anter m it tent, deueif1,(Sickness) U-.S-Strn/ies^ S. 
Cases pe r Month 
per 10,00 0 Soldiers. 
Dy months (all-made 30 days] for a period of S years,Itri- 
fS, the relation of Sickness from fntermi ttent fever, per 
10,000 While froops in the U.S drmles f to the f ver age M~ 
wospher io demperature, and Average daily Range of 
Jemperatare at Stat ions repre s ent mg approicim a te - 
ly the territory occupied by those Jroops. (She num- 
ber of eases represented is lft22.) 
Degrees fa hr. 
Jan, 
rd. 
Mar. 
Apr. 
May 
Jun 
Jul 
Rept 
Oct 
Mou. 
Dee 
flirkness rflueeage. Atmospheric Jentperature 
.Average dail^ Hanqe of J'emperature , Jfb.lO.-Mtmospheric. temperature artel Hange of Temp., and ffri 
^erm itteni fe uerfSi'cknespj,European troops in Endia. 
Casts per Month 
per Io,ooodoldiers. 
iBy months (al! made 30 days) the relation of di eh ness 
from 9rite rmittent feve r per 10,000 European droops 
\in the Jirmy of 9ndia., to the due rape dtrnosphe rt'e 
| Je ir< p e rata re, and due rage daily fauy ofdemper- 
\afuret during the geariXZb.-Jhe curve for range is 
reuersed-the scale increases doomu/ards. (dhe num- 
\her of cases re presented is ZaZd#.) 
Weg rees pahr. 
- <!un. 
id 
-Mat 
-1^ 
Ilan. 
-Jid. 
-od. 
-Vjc. 
Sickness .Average JHrrWspheric Temperature 
Jh/erage daily han^e of Temperafare ......................... J/o.H.- Atmospheric temperature and flange of temp; and 9n~ 
terml t tent Sever (Sickness) /Co. t i v e troops in Snctia, 
Uy months (all made 30 days) the relation of <Sie fo- 
ri e ss from fntermiileni fever per 10.00o Matiu e 
droops m the Mrmy of fndia to the flue rage fltmos- 
yhe ric de my e rat are t and .Average daily flange of temp- 
erature during the year 18?b.. the eurue for range is 
reversed,, the scale increases downwards, fjhe num- 
her of cases re presented ts f!,^3Z.) 
Cases ver AL on th 
■per /OOOP Jo Idle rs. 
\Degrees fahr. 
■ Jan 
■feb. 
Mar 
.Apr 
May. 
Jan 
Tub 
Jug. 
dept 
Oct 
Mon 
Dec. 
Sickness - diuerage dltmospleric temperature. __ _ 
diver age daily Hange of temperature Jfo-12,.- Hange of Atmospheric Temperature, and fntermit- 
ie-nt J e v er (Si ekness) (fori .Apache.,J?..T. 
Cases per Month. 
I Bz/ m on ths,(all made 3 0 days), for a period of S' 
\years HH-io, the relation of Sickness from Jnier- 
mi It ent fever* per /.OOP Soldiers at Sort JJpaehe^.Jl, to 
the JI ver a ge daily hange offemperatureJJhe curve for 
range is reversed^ the scale increases doumcuards. (She 
number of cases represented is only H12. ) 
\ Degrees pahr. 
■ Jan. 
■Feb. 
■Mar 
■Jpf. 
May 
Jun. 
Jul. 
Jhiy 
dtp. 
Oct 
Moi/. 
Jec. 
Sic/cness Average daily Han ye of Temperature , 
* flat a for sickness in manus eripi obtained from Surgetn-'Seneral, 
ll.S.Army. ^Aheie orologg Jrom Heporis for of the. 
Chief Signal Officer at Washington, U.C  
Jan. 
Feb. 
Mar. 
April 
May. 
June. 
July. 
Aug. 
Sept. 
Oct. 
Nov. 
Dec. 
Intermittent Fever 
19-4 
19.6 1 
20.4 
23.6 
24-5 
30-6 
25.6 
32.0 j 
38.5 
36.8 
28.1 
19-3 
Average Range of Temperature 
9-87 
11.55 1 
12.36 
14.88 
i6.io 
15-21 
15-57 
I7-QI 
16.76 
16.41 
13-12 
8.87_ 
Intermittent Fever. ........ 
58-4 
60.8 
62.5 
7°-4 
75-8 
77-8 
79-5 
79-0 
79-o 1 
76.1 
67.0 
58.8 
Average Range of Temperature 
(Mich.). . 
16.34 
18.23 
18.02 
I9-4I 
20.83 
20.62 
20.50 
19-84 
19.74 
17-69 
14-69 
I3-56 
Average Range of Temperature 
(Lansing) 
17-25 
18.29 
18.33 
20.67 
21.72 
20.46 
21.61 
22.05 
22.35 1 
19.81 
15-73 
J3-99_ 
Intermittent Fever 1 
Max. Temperature at I,ansing | 
LSU 
LSU 
70.4 1 
55-7 1 
1 75-8 I 
1 69,2 1 
1 77,8 1 
LZZ^J 
1 79-5 I 
1 ^-3 1 
I 79-o I 
L7919J 
I 79-o | 
1 73-5 J 
1 76'1 1 
61.3 1 
I 67-0 I 
1 43-3 1 
I 58.8 
1 _3L9_ 
Intermittent Fever 
17 
18 
15 
28 
27 
39 
85 
83 
76 
66 
42 
25 
Range of Temperature 
15-2 
16.4 
17.1 
17-5 
18.5 
18.0 
17.2 
17.0 
17-5 
16.4 
16.9 
16.4 
Mean Temperature 
40.4 
44.8 
51-8 
61.3 
70.6 
78.2 
81.2 
_79J_| 
7i-5 
61.8 
49-° 
42-4 
Intermittent Fever 
15 
13 
26 
19 
14 
20 
24 
37 
29 
26 
10 
5 
Average Range of Temperature 
14.10 
16.40 
15.20 
16.10 
16.90 
15-90 
16.60 
16.40 
15-90 
14-90 
14.40 
14.40 
Mean Temperature 
L_3O.4_ 
37-i 
41-9 
53-4 
64.2 
73-o 
77-i 
74-9 
70.1 
59-5 
46.0 
_377 
Intermittent Fever . . • 
26 
32 
3i 
35 
26 
46 
42 
70 
i°5 
68 
5i 
33 
Average Range of Temperature 
8.44 
9-92 
10.86 
10.52- 
11.84 
10.68 
11.28 
10.48 
12.30 
10.54 
9.22 
8.70 
Mean Temperature 
49-9 
5IA 
54-7 
54-8 
57-o 
57-8 
59-3 
58.1 
59-6 
57-5 
54-8 
51-7 
No. 4.-Atmospheric Temperature and Range of Temperature, and Intermittent Fever (sickness), Memphis, Tenn. 
No. 5.-Atmospheric Temperature and Range of Temperature, and Intermittent Fever (sickness), Cincinnati, Ohio. 
No. 6.-Atmospheric Temperature and Range of Temperature, and Intermittent Fever (sickness), San Francisco, Cal. 
TABLES FROM WHICH THE ACCOMPANYING DIAGRAMS WERE DRAWN.1 
No. 1.-Range of Atmospheric Temperature, and Intermittent Fever (sickness) in the United States Armies. 
No. 2.-Range of Atmospheric Temperature, and Intermittent Fever (Sickness) in Michigan. 
No. 3.-Maximum Atmospheric Temperature, and Intermittent Fever (sickness) in Michigan. Deaths from Malarial Diseases 
402 
440 
5°7 
496 
512 
447 
582 
690 
849 
764 
539 
483 
Average Range of Temperature 
13.28 
14.20 
14-54 
16.36 
16.48 
16.92 
15-9° 
15-70 
16.08 
I5-36 
13-90 
13-40 
Mean Temperature 
30.2 
3i-4 
36.8 
47-o 
59-1 
. 68.7 
73-7 
72-3 
65-3 
55-6 
42.6 
33-0 
Deaths from Malarial Diseases 
176 
i93 
196 
225 
208 
191 
204 
258 
325 
297 
247 
216 
Average Range of Temperature 
Mean Temperature 
13.28 
14.20 
14-54 
16.36 
16.48 
16.92 
15-90 
15-7° 
16.08 
15-36 
13-9° 
13-40 
29.8 
3i-i 
_36-4_ 
_47-i 
_58-9_ 
68.6 
_73-5_ 
_ 72*A_ 
-65.5 
_55-5 
42.8 
33-3 
Intermittent Fever 
71-73 
84.69 
88.15 
104.92 
118.49 
135-17 
158.75 
176.94 
200.68 
161.12 
105.20 
67.92 
Average Range of Temperature 
16.18 
17-05 
16.72 
17-92 
18.61 
18.59 
17-92 
16.77 
17-64 
16.51 
16.20 
15-40 
Mean Temperature 
32-0 
L3Z:5_ 
43-8 
L53-4_ 
62.2 
_ 7°-4_ 
_74-2_ 
_72.8 
68.2 
. 58-7_ 
_47-4 
. 39-9 
Intermittent Fever 
168 
I32 
130 
178 
200 
250 
238 
4i4 
45i 
424 
468 
204 
Average Range of Temperature 
34-8 
43-2 
38.4 
41-9 
36.2 
32.4 
20.2 
19.8 
22.6 
27-7 
31-6 
33-5 
Mean Temperature ' 
58.6 
61.4 
69-3 
77-3 
_792?_ 
77- 
_7^5_ 
76.8 
73-i 
66.3 
60.6 
Intermittent Fever 
163 
156 
178 
181 
195 
297 
307 
5i7 
537 
535 
573 
244 
Average Range of Temperature 
34-8 
43-2 
38.4 
4i-9 
36.2 
32.4 
20.2 
19.8 
22.6 
27-7 
31-6 
33-5 
Mean Temperature 
58-6 
61.4 
69-3 
_77_-3_ 
79-2 
_79-2_ 
77-Q 
_76-5_ 
76.8 
_73-L_ 
_^-3_ 
_6o.6 
Intermittent Fever I 
Average Range of Temperature | 
4.62 1 
30.56 | 
9-02 I 
1 30.30 1 
14.771 
3o.86| 
I 14.89 I 11.62 1 
1 35-94 1 38-94 1 
| 17.06 1 
L4i134j 
I 25.59 I 
L.33-84 
I 56-10 I 
28.96 | 
■52.12 I 
1 _ 35-64 1 
40-73 I 
L 34-641 
| 26.691 
L 35-22 I 
7-70 
_ 30.70 
1 More complete headings, and details of the extent and sources of the facts included in these Tables, are given in the diagrams, 
Nos. i to 12, which graphically exhibit the facts which are numerically stated in these Tables. 
No. 8.-Atmospheric Temperature and Range of Temperature, and Malarial Diseases (deaths), in the State of New York. 
No. 10.-Atmospheric Temperature and Range of Temperature, and Intermittent Fever (sickness), European troops in India. 
No. 11.-Atmospheric Temperature and Range of Temperature, and Intermittent Fever (sickness), Native troops in India. 
No. 7.-Atmospheric Temperature and Range of Temperature, and Malarial Fevers (deaths), in New York City. 
No. 9.-Atmospheric Temperature and Range of Temperature, and Intermittent Fever (sickness), U. S. Armies, 1881-5. 
No. 12.-Range of Atmospheric Temperature, and Intermittent Fever (sickness), Fort Apache, A. T. 24 
those made sick are kept sick by still more unfa- 
vorable temperature ranges ; to such an extent is 
this true that the greatest effect of the unfavorable 
range seems to extend to the month following the 
change in atmospheric temperature range. But, on 
the other hand, when the change in the range of at- 
mospheric temperature is is the opposite direction 
-toward lessened range-a condition favorable to 
freedom from intermittent fever, then, at least after 
the first such month, the fever falls nearly with 
the decrease in the range; probably because under 
the atmospheric condition which does not tend to 
cause the chills and fever, those who contracted 
the disease under the less favorable conditions 
tend rapidly to recover under the more favorable 
condition, so there is little or no accumulation of 
cases. 
The evidence in the table and diagram relating 
to the intermittent fever in the U. S. Armies dur- 
ing the late war I consider very powerful, repre- 
senting as they do so many cases among persons 
more than usually exposed to out-door conditions. 
Then, too, the statistics are of cases of sickness 
which must be considered to have a close relation 
to causative conditions, perhaps closer than would 
be the deaths. 
RANGE OF TEMPERATURE SOMETIMES HAS 
DIRECT, SOMETIMES INDIRECT RELATION 
TO INTERMITTENT FEVER. 
Although there is demonstrated to be a direct 
close relation between the daily range of atmospher- 
ic temperature and intermittent fever in Michigan, 
and in that part of this country in which the U. S. 
Armies were during the years 1862, 3 and 4, a 
study of the subject in other parts of this country 
and in other countries where the average daily 
range of atmospheric temperature is either greater 
or less than it is in Michigan, seems to prove that 
in such parts of the world the relationship is 
reversed. 25 
The strongest evidence on this part of the sub- 
ject that I have found is that shown in the tables 
and diagrams relating to range of temperature and 
sickness from intermittent fever in the European 
and native troops in the armies in India, (Diagrams 
Nos. io and n) representing, respectively, 20,268 
and 41,232 cases of intermittent fever which oc- 
curred during a single year, 1886. In the diagram 
(No. 10) relating to the European troops, the 
curve representing the range of temperature is 
drawn as if the relation were direct, but it is 
evident that it is not direct, yet that it sustained 
a well-marked relationship, inversely. [The dia- 
gram has been re-drawn, reversing the curve for 
range of temperature.] 
That it is not the average temperature alone 
that controls the fever is shown by the fact that 
in many of the diagrams the curve for the fever 
has variations for which there are no correspond- 
ing variations in the curve for temperature ; but 
there are variations somewhat similar, although 
sometimes reversed, in the curve representing the 
range of temperature. 
In the diagram (No. 11) relating to the native 
troops, the curve for range of temperature is drawn 
so that the scale increases downwards, and the 
diagram shows somewhat close inverse relation- 
ship between the range of temperature and the in- 
termittent fever. In this diagram, also, there are 
variations in the curve representing fever which 
are not accounted for by the curve for temperature, 
and are better accounted for by reference to the 
curve for range of temperature. That in both 
European and native troops the fever continued 
to prevail until November, notwithstanding the 
changes in both temperature and range of temper- 
ature had occurred three to five months earlier, 
may possibly be accounted for by the accumula- 
tion of cases, in connection with the fact that the 
temperature had commenced its downward move- 26 
ment so that there was increasing exposure to 
temperatures comparatively low. 
HOW DO THE EVIDENCES HARMONIZE ? 
Taking the evidence as it stands it is strong to 
the effect that in Michigan and the U. S. Armies 
the intermittent fever is quantitatively related to 
the daily range of atmospheric temperature, the 
greater the range the more intermittent fever ; and 
that in India the fever is quantitatively related to 
the daily range of temperature, the less the range 
the more intermittent fever. I believe there is 
evidence of a similar reversal of relationship in 
some parts of this country, where the average 
daily range of temperature is very great or very 
little; although the statistics for such places do 
not cover a very great number of cases of sickness. 
In another part of this paper there is an at- 
tempt to learn the conditions which tend most 
strongly toward the production of such a clonic 
spasm of the contractile fibres in the integument 
that loss of body heat is prevented, and the 
spasm or contraction does not yield until after a 
higher than normal internal body temperature 
has resulted. In that part of this paper, the con- 
clusion is reached that the impress which most 
certainly tends to produce this condition of the 
body is the very insidious yet considerable cooling 
of the surface of the body generally ; that sudden 
great changes in temperature (such as occurs in 
winter when one goes from a warm room directly 
into an atmosphere at the temperature of zero), are 
generally reacted against at once, and are not only 
recognized by the senses, but are unconsciously 
guarded against, and especially attract attention 
if confined to a particular small portion of the body. 
One method of resuscitating persons lacking in 
nervous control is to submit them to rapid changes 
in temperature by the alternate application of 27 
hot and cold water, or by other similar means to 
bring about immediate reaction.7 
In physics, I believe the law is that ' ' action 
and reaction are equal and opposite; ' ' but whether 
or not the motion resulting from an action shall 
continue in the same direction, or be reversed in 
direction, depends upon the amount of resistance 
to its continuance, and upon the suddenness of 
the impact. An insidious change in atmospheric 
temperature which cools and constringes the sur- 
face of the body does not, so often as does a sud- 
den change, meet with that resistance or proper 
response by the nervous system which is requisite 
in order that the normal regulation of the body 
temperature shall be brought about immediately. 
If the proper reaction to cold is immediate it is 
useful; but when the reaction comes only after 
the conditions have so far changed that, instead 
of there being cold to react against, heat is being 
applied, then the result is a body temperature ab- 
normally high, in which case, so long as the sur- 
face of the body is cool and purple, we may have 
those sensations and appearances which are called 
chill; but as soon as the reaction is established, 
there is that higher than normal external as well 
as internal body temperature which has long been 
known as fever. 
If we have reached the correct explanation of 
the mechanism of intermittent fever, we have ex- 
plained why it is that in those parts of the world 
where the daily changes of atmospheric tempera- 
ture are usually very great, the body is acclimated 
to and is best able to react against those changes 
which are most pronounced, and least likely to 
react against those changes which are most insid- 
7 In the experience of sudden changes, the system has an impress 
analogous to that given the billiard ball, struck by the cue, when a 
"draw" ball is played; while in the experience of the insidious 
change the system has an impress analogous to that given the ball 
when a " follow " ball is played, in which case the impress contin- 
ues after the ball has struck another, in spite of the opposing force 
which, under the condition first named, served to reverse the direc- 
tion of the motion. 28 
ious. In India, then, and at Fort Apache, Arizona 
Ter., where the average daily range of atmos- 
pheric temperature is excessive, the intermittent 
fever should be inversely proportional to the 
average daily range of atmospheric temperature. 
These statistics seem to prove that this is so. 
On the other hand, in those parts of the world 
where a majority of the daily changes in temper- 
ature are comparatively insidious, but where the 
inhabitants are sb " toned up " that intermittent 
fever is not so often experienced, the greater the 
extent of the daily change in atmospheric temper- 
ature the greater the chance of causing intermit- 
tent fever, through unusual demands upon the 
heat-regulating nerves. In Michigan and those 
other temperate parts of the United States where 
those conditions prevail, the intermittent fever 
should be directly and quantitatively proportional 
to the average daily range of the atmospheric 
temperature. These statistics seem to prove that 
this is so. 
In a few of the tables and diagrams which I 
have studied, there seems to be evidence that 
where the average daily range of atmospheric 
temperature is excessively small, the effect on the 
fever is uncertain. 
In a few of the tables and diagrams there seems 
to be shown a direct relationship of range of at- 
mospheric temperature to intermittent fever in all 
the months in which the average range is below 
about 16°, while in months when the range is 
above that, the relationship seems to be reversed; 
but even in such cases there is apparently good 
evidence that range of atmospheric temperature 
has influence. 
In nearly all the instances studied, it is apparent 
that intermittent fever is more closely related to 
daily range of temperature than to the average 
temperature. It follows, therefore, that if the 
bacteria in the atmosphere alleged to cause the 
fever increase, as stated by Dr. B. Schiavuzzi, in 29 
proportion to the temperature, of the atmosphere* 
then the experience of range of atmospheric tem- 
perature is a stronger controlling factor than is 
the bacillus malarise in the causation of intermit- 
tent fever. 
If, however, the bacillus malariae is capable of 
causing the fever, and it is in the atmosphere in 
proportion to the temperature of the earth (as 
also is alleged by Dr. Schiavuzzi), then we must 
await further evidence, because we have not yet 
sufficient statistics of the proportional prevalence 
of the bacillus in each month of the year at a suf- 
cient number of parts of the world, nor sufficient 
collected and tabulated data of the temperature 
of the earth in different parts of the world, to 
answer the question. 
SUMMARY. 
So far as evidence is yet presented, it seems to 
be proved, then,that: 
i. Intermittent fever is proportional, directly or 
inversely, to the average daily range of atmos- 
pheric temperature. 
2. The controlling cause of intermittent fever is 
exposure to insidious changes, or changes to wffiich 
one is unaccustomed, in the atmospheric temper- 
ature. 
3. In the mechanism of the causation of inter- 
mittent fever, the chief factor is the delay in the 
reaction from exposure to cool air ; this delay, ex- 
tending to a time when greater heat-loss should 
occur, results in the abnormal accumulation of 
heat in the interior of the body, and in disturbed 
nervous action-the chill; and the final reaction 
is excessive, because of the accumulation of heat 
and, sometimes, because it occurs at the warmest 
part of the day. 
4. The fever is the excessive reaction from the 
insidious influence of the exposure to cool air; 
and it is periodical because of the periodicity of 
nervous action, and because the exposure and the 30 
consequent chill are periodical, owing to the night- 
ly absence of the warmth from the sun. 
5. Residence in valleys or on low lands through 
which or upon which cold air flows at night and 
thus causes insidious changes in the atmospheric 
temperature, favors intermittent fever. 
6. In our climate, those measures, such as drain- 
age, which enable the soil to retain warmth dur- 
ing the night, and thus reduce the daily range of 
temperature immediately over such soil, tend to de- 
crease intermittent fever among residents thereon. 
7. In the cure and prophylaxis of intermittent 
fever, those remedies are useful which lessen tor- 
pidity and tend to increase the power of the body 
to react promptly to insidious changes in atmos- 
pheric temperature. 
8. The slowness of the pulse, and other indi- 
cations of torpidity, associated with retention of 
bile or with certain disturbances of the functions 
of the liver, are well known; but, so far as known 
to the writer, these conditions have not heretofore 
been considered as causative of the fever in the 
manner herein suggested.