ZOOLOGY 



and E< histetytiea vr: dyswnleria. Authorities differ as to whether 

 they should be considered as belonging to the genus Ameba or to a 

 distinct genus. 



E. coliis commonly found in the human intestine; as many as 60 

 per cent, of the feces examined in one instance, showing this species; 

 it is apparently not pathogenic. 



E. histolytica is supposed to be the cause of at least one kind of 

 Amebic or Oriental Dysentery; and one of the first warnings one 

 receives in going to the Orient is against eating raw fruits or vegetables 

 unless they have been peeled or have been thoroughly washed. This 

 entameba burrows between the cells of the digestive epithelium or, 

 perhaps, into the cells themselves, by its ameboid activities. (E. 

 buccalis, another species, is found in carious teeth.) 



Rabies, or hydrophobia, one of the most fatal of the diseases to which 

 man is subject, is transmitted, usually by the bite of a dog or some other 

 animal. It was formerly thought that dogs "went mad" from heat, 

 especially during the "dog days;" from having tin cans tied, by mis- 

 chievous boys, to their tails; and from other causes. It is probable 

 that animals never "go mad;" they become infected with rabies only 

 through the bite of some other animal suffering with the disease. In 

 the nerve cells of the brain and spinal cord of animals suffering from 

 rabies are found, by proper staining methods, minute bodies of variable 

 size known as Negri bodies or neurocytes hydrophobiae, Fig. 5. If not 

 the cause of the disease, as many think, they are, at least, a constant 

 accompaniment of it; and it is now possible by them to tell, by the 

 examination of the brain of the suspected animal, whether the human 

 victim should be given the antirabic treatment or not. Formerly 

 it took from two to three weeks to determine whether an animal were 

 "mad;" now the determination can be made in half an hour, which 

 is obviously a wonderful advantage in deciding whether to administer 

 the Pasteur treatment. 



Negri regarded the bodies that bear his name as Protozoa, belonging 

 to the class Sporozoa. Other workers declare them to be Rhizopods 

 the class under discussion. 



In the skin of persons suffering from smallpox are found small 

 bodies that are considered by many to be Rhizopods and to be the cause 

 of the disease. Possibly still other less well-known diseases may be 

 due to the Rhizopods. 



