li>10.] 1)H. 11. B. KAXrilAM n\ AVIAN" Ci )CC| DIOSI.S. 7 1 ."> 



should be noted tliat wliile inncniis disci kii'^c is conimoii. it is not 

 an invariable feature of coL-eidiosis. 



Death from coccidiosis appears to be sudden. Some of the 

 experimental fowl chicks were feeding gi'eedily an hour before 

 death, though dea.th was almost expected from the great emaciation 

 and " bluish" appearance of the birds for some days previous to 

 the actual decease. All infected coi-pses should be burned, i;ot 

 buried. 



IV. IXTERXAL OrcJAXS. 



])etailed examination of diseased birds shows that coccidiosis of 

 fowls, pigeons and young grouse is confined chiefly to the digestive 

 tract, and so is unlike the coccidiosis of the rabldt wjiere lioth the 

 liver and the gut may be affected. 



Dead chicks have shown oval coccidian oocysts (text-iig. 66, 

 p. 714) in the discharge from the nostrils. . Scrapings from the 

 soft palate, trachea and oesophagus of diseased birds have shown 

 the presence of oocysts embedded in mucilnge. Possibly the 

 oijcysts may be regurgitated from tlie gizz.ird or intestine. 

 Oocysts are occasionally present in the crop and gizzard, mixed 

 with crushed food, having been probably taken up with the food. 



The intestine is more highly jiarasitised than any other part of 

 the alimentary tract. The oocysts (PI. LXII. figs. 7, 8, 11, 12), 

 which show much variation among themselves, are softened by 

 the pancreatic juice, the four sporocysts (figs. 9, 10) emerge and 

 from each of them two active, motile sporozoites or germs come out 

 and proceed to attack the epithelium of the duodenum. Having 

 penetrated the epithelium (fig. 1) they become round, grow and 

 produce individuals, destined to divide and give rise to a barrel- 

 shaped mass of active daughter germs, the merozoites (fig. 1, onz). 

 These merozoites separate from one another and infect fresh 

 epithelial cells, the whole mucous membrane being soon badly 

 infested, and becoming reduced to an almost structureless mass 

 (fig. 1). Owing to heavy infection in the duodenal epithelium, 

 death of the young grouse may occur. However, in many cases, 

 some of the merozoites pass into the lumen of the gut and reach 

 the caeca, the tissues of which are similarly mutilated. As far 

 as my experiments go at present, the full period of schizogony 

 would appear to be from 4 to 5 days, as judged by the appeai-iince 

 and general moping of the birds. 



After several generations of mei'ozoites have been produced, 

 the power of the host to })rovide food for the parasite fails, and 

 consequent on this, the latter begins to make preparation for 

 extra-corporeal life and produces large, granular forms, whicli are 

 female mother cells or macrogametocytes (fig. 1, $ ) and somewhat 

 smaller, less granular ones which are microgametocytes (fig. 2, S)- 

 Each macrogametocyte gives rise to one passive macrogamete or 

 female element (fig. 1), while each microgametocyte gives rise to 

 many minute, motile microgametes, the male elements (fig. 2). 

 Fertilisation (fig. 3) occurs through a niicro])yle left in the wall 



