1910.] UK. JI. I!. I'AXTJi.VM OX AVIAN f'oCC lUIoSIS. 715 



in grouse, whieli is identical with tlie parasite found in •' wliite 

 (liaTi'luea " of fowls, also vaiy among themselves. Usually the 

 oiieysts are ov-al (figs. 4-8), but a series of varying sizes and shapes 

 can readily be found (figs. 8, 11, 12, 14), while round oocysts also 

 occur (fig. 11). The exact shape and size of the oiicvst is a factor 

 of the space in the cell available for the development of the 

 macrogamete, and should not be insisted upon as a specific character, 

 for where many parasites are aggregated together in a limited area 

 of epithelium, the macrogametes and oocysts ai-e small, while in 

 area,s of the gut but poorly parasitised, large oocysts })repondera.te. 

 Nutrition of the parasite has obviously a great influence on both 

 its size and its propagative power. 



In some cases the gut-wall is extremely' thin and tender; in 

 other birds this effect is not marked. Inflammatory patches may 

 be seen at intervals, particularly in the caeca, and the ca^ca usually 

 are enlarged. At the ileo-csecal junction, where a recuii-ence of 

 schizogony and sporogony occurs, much degenerated epithelium is 

 present in the gut contents, and this epithelium contains both 

 schizonts and gametocytes. 



The large intestine of chicks infected with coccidiosis sometimes 

 shows inflammatory patches and blood may be pi-esent in the 

 rectal contents. The rectum itself seems ra,rely to be attacked 

 by E. avium, though its contents usually contain oocysts. 



The kidneys, spleen, liver, and gall-bladder of birds sufl'er- 

 ing from coccidiosis ne^ei" contained Elmeria, though the spleen 

 and gall-bladder were sometimes enlarged. Examination of 

 the generative organs has shown no stage of E. avium so 

 far, though it is possible tha.t eggs may become contaminated 

 during their passage through the cloaca, of the mother. The 

 young chicks then might be hatched in contact with infectious 

 material, and so acquire coccidiosis early in life. Eight da}s old 

 grouse chicks were the youngest naturally infected chicks that I 

 examined. The period of 8 to 10 days is the one determined 

 roughly by my experiments as being required for the complete 

 developmental cycle of E. avltmi in fowls and pigeons, from the 

 time of ingestion of the oocysts to the excretion of the maximum 

 number of oocysts of the second generation. 



Many bacteria are present naturally in the gut of the grouse, 

 and their active movements can be well seen, especially in the 

 cppcal contents of freshly killed grouse. Examination of sections 

 of the gut of the grouse, especially of sections stained with iron- 

 luematoxylin and iron hiematoxylin followed by van Gieson's stain, 

 reveals the presence of numerous bacteria which ai'e present, not 

 only in the lumen of the gut, but forming a layer along the 

 sti'iated edge of the columnar epithelial cells, and also are found 

 in lesions left by the outward passage of gametes and merozoites. 

 These bacteria may have a harmful effect on the tissues invaded, 

 and there is evidence to show that they gain access to the tissues 

 very early, the sporozoites and merozoites acting, in fact, as 

 inoculating needles, whereby the injurious bacteria are passed 

 into the tissue of the gut, whence, by way of the blood and lymph, 



