l86 POULTRY DISEASES AND THEIR TREATMENT. 



cycle, as shown by the shorter arrow from 7a to 5 may be re- 

 peated any number of times. 



If, however, the conditions are not very good, i. e., the bird is 

 about to die the sporozoids undergo an entirely different devel- 

 opment as shown at numbers 7 to 15 (fig. 44). Here the sporo- 

 zoids enter the epithelial cells and some develop into very large 

 (sg?) cells (female element) as shown at 8, 9 and 10. Others 

 go through the development shown in 8a, 9a and loa, forming 

 a very large number of minute motile zooids or sperms (male 

 element) which unite with one or more of the large ^gg cells 

 as shown at 11. After this sexual union there is developed 

 the oocyst like No. i, with which we started. At all stages of 

 this disease many of these cysts are carried to the outside with 

 the feces and upon being picked up serve to infect other chicks. 

 Death is caused by the parasite attacking so miany of the intes- 

 tinal cells that the chick is no longer able to digest its food. 

 There are also secondary effects by which the kidneys are de- 

 ranged and throw out a large amount of white urates, hence the 

 name "white diarrhea." 



Diagnosis. The symptoms of coccidiosis are similar to those 

 of other forms of white diarrhea, (cf. p. 189). The only 

 exception is that according to Morse the ceca are always dis- 

 tended with yellowish-white cheesy matter. In other forms of 

 white diarrhea this may or may not be the case. These differ- 

 ent forms of white diarrhea have been too little studied yet to 

 permit of an exact differential diagnosis on external symptoms 

 even supposing that ever to be possible. With the aid of a 

 microscope the finding of coccidial cysts in the fecal matter 

 would indicate that these were causing the. disease. 



Dr. Hadley has carried out some feeding experiments with 

 these coccidia and has found that he is able to produce the dis- 

 ease in chicks more than two daj^s old. As will be mentioned 

 later (p. 188) it is said that infection with the bacterium of 

 bacillary white diarrhea cannot take place after the chick is 48 

 hours old. It is possible that further work will show that these 

 facts are of some importance in distinguishing these two forms 

 of the disease. 



Bacillary White Diarrhea. 



In May, 1908, Dr. L. F. Rettger and Mr. S. C. Harvey pub- 

 lished a paper on "Fatal Septicemia in Young Chickens or 



