THE POPULAR HEALTH MAGAZINE. 
337 
THE ANIMAL PARASITES WHICH WE OBTAIN 
THROUGH OUR FOOD. 
A Lecture; Before the Sanitary League oe Washington, D. C. (Abbreviated). 
Zoologist, Bureau of Animal Industry U. S. Department of Agriculture, 
Ch. Wardell Stiles, Ph. D 
AS I am to show you some of the ani- 
mal parasites which we may obtain 
from food, permit me to invite you all to 
lunch with me for half an hour or so that 
you may see some of the wonderful ob- 
jects it is possible for us to swallow with- 
out knowing it. The repast, to which I 
now invite you, is not such a one as you 
would yourself prepare, but it is one 
which might be prepared by the ignorant 
and slovenly servants of ladies who con- 
sider it a disgrace to know anything 
about household matters. For your 
comfort, however, I will tell you that a 
number of the parasites which I shall 
mention are not found in Washington, 
except as specimens in the various scien- 
tific collections. 
Our first course consists of soup—let 
it be any kind you wish, bouillon, mock- 
turtle or anything else. As we are about 
to take a spoonful we notice a curious 
object floating around in it, which upon 
closer inspection turns out to be a small 
beetle (Blaps mucro nata) closely related 
to our death-watch beetle. If we swal- 
low this bug, the insect itself would not 
injure us in the slightest, for it would be 
digested, but according to the investiga- 
tion of an Italian zoologist, a little or- 
ganism lives in this insect which upon 
coming into our digestive tract and be- 
coming free from the body of the bug, 
develops into the parasite known to the 
scientist as a thorn-headed worm (Echi- 
norhynchus moniliformis). This is a curi- 
ous worm, about 2 to 4 inches long, with 
a strong proboscis on its anterior end, 
armed with several rows of hooks. Tike 
many other parasites, it possesses no in- 
testine, but, fastened with its head in 
the wall of our digestive tract, it floats 
in the contents and absorbs nourishment 
through its entire outer surface. For 
your comfort, I will state that this is not 
a common parasite in man, but lives in 
rats. The rats scatter the eggs around, 
and these are swallowed by beetles, in 
which the larval form develops. When 
the insects are eaten by rats, or persons, 
the larvse then develop into the adult 
and the life-cycle is thus completed. It 
may be interesting for you to know 
that when the Egyptian ladies wish to 
become stout, they are said to eat a 
beetle of this genus, and thus they lay 
themselves open to possible infection 
with these worms. Perhaps instead of 
finding a Blaps in our soup, we dis- 
covered some other bug, say a small 
butterfly, by the name of asopiafarmalis, 
or a beetle known to scientists as akis 
spinosa. In that case, instead of becom- 
ing infected with the thorn-headed worm, 
we should have caught a small tape- 
worm (Jlymenolepu). 
You may think I have stretched a 
point by saying that these bugs may be 
found in soup, but I assure you that it 
is not an uncommon occurrence to find 
insects in soup, and that people swallow 
these insects, containing the germs of 
various parasites, is shown by the fact 
that the parasites I have mentioned 
occur in man, and that the only way he 
could possibly catch them is by swallow- 
ing the insects I have referred to. 
While our soup plates are being re- 
moved we unconsciously nibble at a piece 
of bread, at the same time that we are 
discussing the weather or some other 
equally exciting topic. Now let us sup- 
pose that this bread was cut by our cook 
—who, as I intimated, is not the most 
cleanly person in the world. The cook 
may herself be infected with pin-worms; 
she has unconsciously gotten some of 
the microscopic eggs upon her hands, THE POPULAR HEARTH MAGAZINE. 
338 
and in cutting the bread has uncon- 
sciously transferred them to the bread. 
They are too small for us to see, and in 
eating the bread, we accidentally become 
infected with these germs. Pin-worms 
(Oxywris vermicular is) are among the 
most common animal parasites found in 
human beings; probably fully one-fourth, 
possibly one-tliird, of the persons in this 
room have at some time during his or her 
life-time harbored these creatures. If only 
a few worms were present, we were not 
troubled very much, but if many were 
present we probably were quite unhappy 
for the time-being, notwithstanding the 
enormous doses of soothing syrup or 
other mixture which our well-intending 
mothers gave us to keep us from being 
so restless during the night, little sus- 
pecting what the real cause of our rest- 
lessness was ! These parasites are, as I 
said, very common and may be obtained 
through solid food which has been 
handled by persons who are affected 
with them, and are not careful enough 
about washing their hands, or they 
be obtained through unfiltered or un- 
boiled drinking water, or through milk 
when the milk-can, before leaving the 
farm, or even afterwards, has accident- 
ally (?) stood for-a few minutes too near 
a contaminated water supply. 
If our servant has allowed the lid of 
the bread-box to stand open, and mice 
have gotten in there, they have scattered 
on the bread microscopic parasites 
known to the zoologist as Megastoma 
intestinale and as we eat the bread we 
become infected with these germs also. 
Our fish has now been served. Some 
of us have taken pike, others have taken 
turbot, still others have chosen some 
other fresh-water fish, but the essential 
point is that the fish has not been cooked 
enough. As we are eating this fish, one 
of us, who perhaps has sharper eyesight 
than the rest, discovers a white object 
about one-fourth to one-half inch in 
length, which differs slightly from the 
muscle. This object upon closer inspec- 
tion proves to be the germ or larval stage 
of the broad Russian tape-worm (Bothri- 
ocephalus latus),which is the largest para- 
site found in man. The worm grows to be 
32 feet in length. I spoke of it as a worm. 
In ordinary parlance we generally call a 
tape-worm a single animal, but scien- 
tifically speaking, the tape-worm is a 
colony of animals. The head, pro- 
vided with two suckers by means of 
which it holds fast to the wall of our 
intestinal tract, is what we have swal- 
lowed as a germ or larva, with the fish, 
and represents the mother of the colony; 
while these segments, of which there 
may be hundreds, each represent indi- 
vidual worms of a second generation, 
the mother and all her daughters remain- 
ing joined together as a colony. It may 
be a satisfaction for you to know that 
this parasite is rare in America. 
As our fish-plates are removed and 
we are waiting for the next course con- 
sisting of meats, we introduce a new 
topic of conversation, by taking a sip 
of unfiltered and unboiled water. It 
would have been better, perhaps, had we 
not taken that particular drink, for we 
have run the risk of swallowing the 
germs of a number of different parasites. 
We might perhaps have swallowed 
the eggs of the ordinary lumbricoid 
worm {As car is lumbricoides), of which 
I show you several specimens in this 
bottle, and of which you see some fig- 
ures on this chart. This is one of the most 
common of the parasites found in the 
human species. I do not know how 
common it is in Washington, but I have 
records of examinations of 7547 persons 
in certain European cities, and of this 
number 962 persons, or 12.7 per cent., 
or about one person in every eight, were 
infested with this worm, and there is no 
reason to suspect that the worm is any 
less frequent in this city. It is espec- 
ially frequent among school-children, 
negroes and idiots, in fact among all 
classes of people who are not cleanly 
about their personal habits, and who 
drink unfiltered or unboiled water. In 
cities like Paris, where the entire water 
supply is filtered, the worm is exceed- 
ingly rare. 
If we happened to be in or in 
certain parts of Asia, we might have be- 
come infested with another worm, the 
guinea-worm by name (.Dracunculus 
medinensis), which some scientists look 
upon as the fiery serpent of the children THE POPULAR HEALTH MAGAZINE. 
339 
of Israel. This parasite, of which 
there is probably only one specimen 
in the United States, is about a yard 
long and lives under the skin; it pro- 
duces large swellings, accompanied by 
an intense burning sensation, hence the 
name fiery serpent or fiery dragon, which 
it retains to the present day. The 
parasite is caught by swallowing small 
crustaceans in unfiltered drinking water, 
for the larval stage of this worm lives 
in these minute crabs, Cyclops by name. 
Although we are not liable to catch 
the fiery serpent of the children of 
Israel in this part of the world, there is 
a somewhat similar parasite which we 
do stand in danger of catching. This 
worm, which scientists call a thread- 
worm (Filaria sanguinis hominis), lives 
in various parts of the body; the young 
embryos of the worms are found in the 
blood and are so small, about 1-1000 of 
an inch long, that a large number may 
be found in a single drop of blood. Now 
when mosquitoes bite a person infected 
with these worms, the insects swallow a 
number of these microscopic germs along 
with the blood. The worms grow some- 
what while in the body of the mosquito, 
andthen when Mrs.Mosquito, afterspend- 
ing four or five days digesting her meal, 
goes to some body of water to deposit 
her eggs, the worms are ready for the 
next step in their life-history. After 
the mosquito dies and falls into the 
water, the young worms devour the in- 
ternal organs of the insect, leave the 
mosquito and swim around until they 
are swallowed by the person who is care- 
less enough to drink unfiltered or un- 
boiled water. 
In some other parts of the world an- 
other very curious animal is caught 
from the water, an animal about half an 
inch long, which spends its earlier stages 
in a small crab, but which after being 
swallowed by man lives in the large 
veins in his abdomen and causes a very 
serious disease. 
But we have caught enough parasites 
from that drink of water—let us pass on 
with our lunch. We have before us on 
the table a number of different kinds of 
meat. Some of us may prefer tongue 
or roast beef; others may prefer pork of 
some kind, say roast pork, boiled ham, 
or if we are inclined towards German 
customs we may take some duck stuffed 
with sausage. L,et each one select his 
or her own meat and I will tell you 
what parasite you have swallowed, tak- 
ing it for granted that all of the meats 
are underdone. 
Those who have chosen beef in any 
form, as tongue, roast beef, smothered 
beef, steak or stuffed veal, etc., have 
run the risk of catching the so-called 
beef-measle tape-worm ( Tcenia saginata). 
This is the most common of the eight 
different species of tape-worms found in 
man. It is generally about fifteen to 
thirty feet long and is made up of a 
head and about 1200 to 1300 segments, 
each one of which you will recall repre- 
sents a separate worm. These small 
bladder-like structures, about the size 
of a small bean, resemble bits of fat 
to a certain extent. These are the objects 
you swallow when you catch a beef- 
measle tape-worm. This cyst contains 
a tape-worm head, bearing four suckers. 
When this is swallowed segments begin 
to form very rapidly. In treating for 
tape-worm it is always necessary to get 
rid of this head, for if that remains in 
the body the tape-worm will grow 
again. 
Those of us who chose pork chops, roast 
pork, ham or duck stuffed with pork sau- 
sage, have of course escaped the danger 
of becoming infested with the beef-measle 
tape-worm, but have run the risk of 
catching a smaller but still more dan- 
gerous tape-worm i. <?., the pork-measle 
tape-worm ( Tcenia solium). The object 
we swallow in this case is almost iden- 
tically the same as the object we would 
have swallowed had we eaten beef. The 
bladder-worm ( Cysticercus cellulosce) lies 
in the muscle, surrounded by connective 
tissue, and as it comes into our stomach, 
the surrounding cyst is digested. The 
head and neck pass to a point in our diges- 
tive tract a little way below our stomach 
and then begins the formation of seg- 
ments, the segments always forming near 
the head, so that the last segment, that is, 
the segment furthest from the head, is 
the oldest, while the segment nearest 
the head is the youngest. THE POPULAR HEALTH MAGAZINE. 
340 
I said that this tape-worm is more 
dangerous than the beef tape-worm. Not 
because it causes 11s more pain while in 
the digestive tract, however, but because 
the microscopic embryos, which are 
formed in the segments, can under cer- 
tain conditions bore through the intes- 
tinal wall and reach the inside of the 
eye or some other part of the body, and 
there develop into a bladder-worm. In 
this way man as well as hogs may be- 
come infested with pork-measles. 
But this is not the only parasite we 
have run the risk of catching in eating 
half-cooked pork. We may have eaten 
a piece of meat infested with the much 
dreaded trichinae. 
These trichinae are curious little crea- 
tures, and although they are objects of 
considerable fear to the who 
knows only too well that if these para- 
sites once gain access to a patient’s 
muscles, he is utterly powerless to reach 
them and kill them with any medicine 
known, yet to the zoologist these worms 
are of considerable interest. 
They are very small, as you will be- 
lieve when I state that as many as 350,000 
may live in a single pound of meat. 
These minute worms live inside of the 
muscle-fibre of pork, coiled up like a 
spiral, with a small cyst around them. 
When we eat this pork, the meat upon 
coming into our stomach is digested and 
these minute cysts are liberated. The 
juices of our stomach then dissolve the 
cysts and Mr. and Mrs. Trichina pass 
down below our stomach and proceed to 
make life unpleasant for us. Mrs. Trich- 
ina becomes the mother of about 10,000 
to 15,000 wriggling youngsters within a 
month’s time and these latter bore 
through our digestive wall and journey 
to the muscles. Upon arriving at some 
muscle which find to let, they bore 
into it and proceed to take possession of 
the contractile substance. The more of 
the contractile substance the trichinae 
eat, the less there is for us to use in 
swallowing, breathing, walking, etc. 
After some weeks, however, the parasites 
have satisfied their appetite and they be- 
come enc37sted, and our muscles present 
the same appearance which the pork had 
before we ate it. If our physician has 
succeeded in stimulating us up to the 
stage when the parasites become en- 
cysted, we will recover from the disease, 
and the trichinae will do no further harm, 
until we go to Africa as missionaries, 
when the savages may suddenly discover 
that they have a bad case of trichinosis, 
should they not allow us to carry on our 
work unmolested. I should not, however, 
advise that we require candidates for the 
missionary field to first become infected 
with trichinae in order to discipline the 
cannibals, but had our first delegation 
of missionaries passed through the dis- 
ease of trichinosis before going to their 
fields of labor, the savages would by this 
time have learned that it was dangerous 
to use missionaries as an article of food. 
I stated that we obtained our trichi- 
nae from half-cooked pork, but you may 
wonder how the hogs became infected. 
The matter is very simple indeed. 
These parasites are also found in rats, 
and as the hog is very fond of rats as a 
delicatesse, the hogs catch the parasites 
by eating rats. Rats keep up the infec- 
tion among themselves by eating each 
other, for rats are cannibals. 
We have perhaps not noticed that the 
odor of the meat brought our favorite 
dog into the dining room. He is prac- 
tically a member of the family and pet- 
ted by all, none except the scientist 
looking upon him as anything except a 
most faithful friend, old Dog Tray ! 
The scientist, however, is hard-hearted 
enough not to appreciate this friendship, 
and believing the proper place for a dog 
is the cellar, the barn-yard, the dissect- 
ing room or the dog-pound, he hygieni- 
cally looks upon the dog as his enemy. 
Nevertheless some of you do not share 
these opinions and as the dog comes to 
you, you pet him and allow him to snif- 
fle and lick your hand. But let us look 
for a moment at the animal parasites 
which the dog has given to during 
that short caress ! 
Beloved old Dog Tray has in his nose 
a parasite about two to five inches long, 
a so-called tongue-worm (Linguatula 
rhinaria)\ in sniffling and licking 3-our 
hand he has deposited there some micro- 
scopic eggs, and the next time you take 
a piece of bread 3-ou will transfer these THE POPURAR HPRVRTH MAGAZINE. 
341 
eggs on the bread to your mouth. The 
eggs will be swallowed and the germ 
will bore from your digestive tract into 
your liver, and there develop into a 
parasite about one-quarter to one-half 
an inch long. 
Or in caressing the dog you have un- 
consciously gotten a flea or a louse upon 
your hands, perhaps under your finger- 
nails, and later you have swallowed that. 
It may now be a comforting thought for 
you to know that inside of that flea or 
louse there lives the larval stage of a 
tape-worm (Dipylidiuni caninum) with 
which you have become infected. But 
that is not all. 
The most dangerous animal parasite 
which man has, is a so-called hy- 
datid, which is the larval stage of a 
small tape-worm ( Taenia echinococcus), 
found in the dog. From the very 
nature of the habits of the dog we 
must not be surprised to find the eggs of 
this tape-worm upon his coat. Petting 
him, you get these eggs upon your 
hands ; from your hands to your mouth 
is but a short distance ; you swallow the 
eggs and have become infected with the 
dreaded Echinococcus! The echinococcus 
develops in your liver, in your lungs, in 
your brain or elsewhere and you sud- 
denly discover the fact too late—perhaps 
it is not you who discovers it after all, 
but the physician who makes your post- 
mortem, that the dog is your enemy 
rather than your friend. I am not now 
referring alone to the miserable collec- 
tions of animated bones and dog-skins 
which wander into our city from Virginia 
and Maryland, but I refer to mamma’s dar- 
ling little poodle as well. In fact, from 
statistics it appears that this hydatid 
parasite to which I refer is most frequent 
among the dirty Icelanders who live in 
the same huts with their dogs, frequently 
sharing the same plate, and next in fre- 
quency in women who keep pet lap-dogs. 
But our salad has come on the table. 
This salad—let it be any kind you pre- 
fer—was grown in a rather damp field; 
the year was perhaps an unusually damp 
year; and Bridget or Amanda is particu- 
larly lazy to-day and did not wash the 
salad as well as she would have done, 
had she expected that you would inspect 
the various courses before they came on 
the table. Let us see what parasites we 
swallow this time. 
First of all, we swallow a most remark- 
able animal, known as the common liver- 
fluke (.Fasciola hepatic a), a parasite which 
is not particularly frequent in man but 
one which is more common in sheep and 
cattle. A parasite which in 1830 killed 
more than 2,000,000 sheep in England, 
causing an estimated loss of $20,000,000; 
and one which killed 1,000,000 sheep in 
Buenos Ayres in 1882; a parasite which 
kills hundreds of cattle and sheep in Texas 
every and has recently swept off 
nearly all the cattle on some of the Sand- 
wich Islands. This parasite lays about 
45,000 eggs, in each of which, under fav- 
orable conditions, a small ciliated em- 
bryo develops; this embryo swims around 
in the water until it finds a certain 
swamp-snail, into which it bores its way. 
Upon coming to rest (as a sporocyst) it 
produces a third generation (redia) which 
is however very unlike the first or second. 
This produces still another different 
generation (cercaria) which leaves the 
snail and encysts itself upon some plant, 
say the kind used in our salad. When 
we swallow this cyst, the animal seeks 
out our liver and developing into the 
adult, proceeds to make trouble for us. 
Nor is this the only fluke which we 
might catch in eating salad. A smaller 
one, the lancet-fluke of Germany (Dis- 
toma lanceolatum) or the Japanese liver- 
fluke (D. sinense) may be gotten in this 
way. The Chinese lung-fluke, which 
also lives in cats and tigers and which Dr. 
Ward has recently found in this country, 
might make their homes with us, brought 
to us by improperly prepared salad. 
But I have introduced enough para- 
sites to you to show you the necessity of 
preparing food carefully before it is 
placed upon the table. I hope I have 
not taken your appetites away for your 
meals to-morrow by making you disgusted 
with food, although I cannot say that I 
should feel very sorry if I have made you 
disgusted with pet dogs. Remember, 
that if your food is properly prepared, if 
your drinking water is boiled or filtered, 
and if you keep dogs from becoming too 
intimate friends with you, there is abso- 342 
THE POPUEAR HEARTH MAGAZINE. 
lutely no danger of your catching any of 
these parasites that I have mentioned, 
but, if you will insist upon allowing 
your pet poodle the privileges of the 
dining room, if you are careless about 
boiling or filtering your drinking water, 
and if you allow your careless servants 
to prepare your food as they wish, you in 
the meantime feeling it beneath you to 
enter the kitchen and see how matters 
are going on, you lay yourselves open to 
infection not only by these parasites of 
which I have spoken, but by many 
others. 
THIS again is the season when milk re- 
quires such careful inspection. The 
sick, the young and, indeed, so many 
persons rely on city milk for food and 
nourishment, that the food inspectors 
should be doubly alert to detect impure 
milk. Unfortunately it is only by bac- 
teriological tests that some of the most 
dangerous contaminations of milk can be 
found and as this requires special skill 
and consequently entails increased ex- 
pense, there are few places that can af- 
ford the cost. Typhoid fever, that wast- 
ing and destroying disease, that has just 
played such havoc in Montclair, Buffalo 
and other places, is caused by impure 
milk infected with contaminated water, 
and this a bacteriologist alone can detect. 
The chemical tests may show a pure ar- 
ticle and the lactometer may register at 
normal and yet the deadly typhoid germ, 
long-lived and very resistant, cruelly 
awaits its victim in this apparently pure 
liquid. Boiling milk is a thoroughly 
protective method but the means of in- 
spection in every place should be so per- 
fect that boiling would not be neces- 
sary. 
cooked at home or under the supervision 
of some one to be trusted. As for ice 
cream poisoning, it is very hard to say 
when it may occur and there is no known 
means to prevent it; one sample may con- 
tain poisonous properties and another be 
free from them. On the whole, when a 
reliable dealer supplies the ice cream and 
it is known that the milk and other in- 
gredients are fresh, the chances of poison- 
ing are much less. It is often that 
sharp competition in supplying large 
gatherings with food at a picnic or excur- 
sion leads to poisoning. This subject 
comes under the general head of food in- 
spection, and when States and cities pass 
and enforce laws for the proper in- 
spection of food and drink, then will the 
chances of poisoning be reduced to a 
minimum. 
BAETIMORE has been visited by a 
short attack of small-pox, which 
the efficiency of the health commis- 
sioner’s staff has kept completely in 
check. The disease started with some 
colored members of a theatrical troup 
and spread to others of the same race 
and to a few white. This reminds us 
that the African race is peculiarly sus- 
ceptible to small-pox, just as it is es- 
pecialty proof against yellow fever. 
Therefore the cities like Washington, 
Baltimore and southern cities in general 
should be on their guard and vaccinate 
promptly and effectively. 
THE time is now at hand when cases 
of supposed poisoning by icecream, 
crabs and other articles of diet will be 
announced by the daily press. These 
are generally cases of actual poisoning, 
but not such as occur from real poisons 
placed with evil intent. The poison- 
ous substance may be evolved by a 
chemical change in the food either 
before or after it is taken into the stom- 
ach. It is no easy matter to tell with 
accuracy when crabs were picked and 
the opportunities for unscrupulous dealers 
in hot weather to work off stale crab meat 
in shells are very favorable and the temp- 
tation is very strong. If crabs must be 
eaten, they should be bought alive and 
BEFORE long, Asiatic cholera, like 
the Asiatic plague, the Bubonic 
pest, and their modern correlative, typhus 
fever, will become extinct among Euro- 
pean nations, and survive only as the 
records and relics of a historic shame, 
says one of the greatest of modern sani- 
tarians. Cholera, being a preventable 
disease, is a reproach to any nation.