28 BULLETIIif 817, U. S. DEPT. OF AGRICULTURE. 



The present Avriters have also observed the common occurrence of 

 pneumonia in animals that have been fed with AscaHs 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 AsoaHs 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), it seems quite probable that 

 Ascaris larvae 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 

 I'emarked, experiments in infecting children with Ascaris^ such as 

 those carried out by Mosler and by Epstein (1892), are highly repre- 

 liensible. Even though Mosler and Epstein were unaware of the 

 fact that Ascaris larvae may cause a dangerous and possibly fatal 

 affection of the luiigs,. 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 larvae, though the fact that the larvae 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 AsoaHs 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 



