CROSS-INFECTION EXPERIMENTS 105 



Davaine, 1875, is very similar to T. muris, exhibiting the same 

 coarse structure and it forms cysts which are also formed by T. 

 muris. Experiments should be designed to determine whether or 

 not these are cross-infective, ChUomastix intestinalis Kucznski, 

 1914, has also been described, and Emhadomonas has been observed 

 by Wenyon (1926). The common coccidium of the guinea-pig ob- 

 served by the writer resembles more closely an Eimeria found in 

 the rat than any in rabbits. This is probably the one named E. 

 cavicB by Sheather in 1924. The BaJantidium of the guinea-pig has 

 been named B. cavice by Neiva, da Cunha and Travassos (1914). 

 Whether all the above forms can be accepted as representing dis- 

 tinct species will depend on further accurate morphological dififer- 

 entiation and on transfer experiments. These appear to be of 

 immediate interest especially \\n\h rabbits and rats. 



7. AVES 



Hegner's (1928c?) recent experiments with chicks in which he 

 has established experimental infections of protozoa from several 

 different mammals in young negative chicks opens up an excep- 

 tionally interesting and valuable field for investigation in the study 

 of relationships between the intestinal protozoa of birds and mam- 

 mals. Of immediate practical importance is the possibility of the 

 fowl's serving as a reservoir host for human flagellate infections. 

 Another problem of special importance is cross-infection with in- 

 testinal cocciDiA between domestic rabbits and domestic fowls, both 

 often being raised in close proximity on the same farm and both 

 suffering from severe intestinal coccidiosis. A preliminary report 

 of work being carried on in the writer's laboratory on this problem 

 indicates that chicks at least are not readily infected with rabbit 

 COCCIDIA, for twelve chicks fed ripe oocysts from all four species 

 of intestinal coccidia of rabbits have failed to acquire the infection. 



