72 Disca,se.s' of Potdtry 



birds occurs by contamination of the food, water, gravel, 

 and other substances taken into the digestive organs. The 

 coccidia multiply with great rapidity in the intestines of 

 diseased birds, and enormous numbers are discharged with 

 the droppings and are carried on the birds' feet to the feed 

 troughs and drinking fountains unless these are well pro- 

 tected and of such form that they cannot be reached by the 

 feet. Under any circumstances they are spread over the 

 floor of the houses and the surface of the runs, and many will 

 be picked up with gravel, grain, and other substances. The 

 germs are found in the part of the small intestine nearest 

 to the gizzard, where they cause inflammation, with redness 

 and thickening of the intestinal wall. They are also found 

 in the ceca, which are frequently thickened and distended 

 with a whitish, yellowish, or greenish yellow, pasty mass. 

 After two or three weeks the disease may extend to the liver 

 and lungs, where it is recognized by whitish or yellowish 

 spots or by large cheesy nodules. Geese are attacked by 

 another species, which causes nodules in the kidnej^s. 



The life history of a coccidium is very complicated, yet 

 in order to combat this parasite most successfully it is neces- 

 sary to know something of its life history. Figure 8 repre- 

 sents the different stages in the life history of one of these 

 parasites. If one should examine with a microscope the 

 contents of one of the ceca of a bird which died with a form 

 of coccidiosis he would find forms somewhat like No. 1 

 in the figure. 



These are the oocysts or permanent cysts of the coccid- 

 ium. The membrane around the outside of this cyst is 

 very tough and will withstand almost all methods of disin- 

 fection. It will live and even grow in sulphuric acid. It 

 can be killed, however, by drying. The size of one of these 

 cysts is between 2 5To7 and ^-^qq^ inch. If this cyst is placed 

 under the right conditions for development the first step is 



