28 BULLETIN 817, U. S. DEPT. OF AGRICULTURE. 
The present writers have also observed. the common occurrence of 
pneumonia in animals that have been fed with Ascaris eggs, reference 
to which has already been made in a former paper (Ransom and 
Foster, 1917). The symptoms of pneumonia appear within a few 
days, usually about a week, after the ingestion of the eggs, and the 
animal may die within a day or two after the first symptoms are 
observed. | 
Among pigs very young animals seem more liable to develop se- 
rious cases of Ascaris pneumonia than older animals, Our worst. 
cases among pigs have been in sucklings. » 
In. view of the results of experiments on various animals (rat, 
mouse, guinea pig, rabbit, pig, goat), 1t seems quite probable that 
Ascaris larve are capable of causing pneumonia in human beings, 
particularly in children. Evidence that they may cause lung trouble. 
in human beings is found in the fact that Mosler (in Leuckart, 1867) 
observed the occurrence of dyspnea among children to whom he had 
given Ascaris eggs a few days before. As Stewart has very properly 
remarked, experiments in infecting children with Ascaris, such as 
those carried out by Mosler and by Epstein (1892), are highly repre- 
hensible. Even though Mosler and Epstein were unaware of the 
fact that Ascaris larve may cause a dangerous and possibly fatal 
affection of the lungs, their use of children as experimental animals 
can not be justified. Lutz (1888) has recorded the occurrence of 
symptoms in a young man who volunteered as a subject for experi- 
ments with Ascaris that were in all probability related to the inva- 
sion of the lungs by the larvee, though the fact that the larvee migrate 
through the lungs was, of course, not known to Lutz. 
Lung affections, including the condition commonly known as 
“thumps,” are of very common occurrence among young pigs, result- 
ing in numerous deaths. These are undoubtedly often caused by 
Ascaris infection, and, in fact, numerous natural cases corresponding 
exactly to cases of experimental infection, have been observed by 
Dr. H. B. Raffensperger, of this bureau, in the course of investiga- 
tions carried out by him under direction of the Zoological Division 
in various localities in the field. Ascaris is a common parasite and 
the soil in places occupied by pigs is liable to be heavily laden with 
the eggs of the parasite. There is consequently plenty of oppor- 
tunity for newborn pigs to become infected. Dirt from the pigpen 
adheres to the skin of the sow, and the young -pig in suckling swal- 
lows not only its mother’s milk but also Ascaris eggs from the dirty 
teats. In addition, many eggs are likely to be picked up by the 
young pig in rooting about in the soil of the pigpen. It would 
therefore seem that greater care of the sow and the pigpen with 
reference to cleanliness, by reducing the chances of infection to which 
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