712 Dlt. II. I!. I-ANTIIAM ()\ AVIAN (Of (I DK i.SlS. [MilVO. 



wlieii adult wi'igheil 4 11). ',) oz., wjiilr its .si.ster Ijinl that ai-ted as 

 control weighed 5 Ih. 4 oz. 



Besides loss of weiglit the infected birds become antpuiic. 

 The cere, comb, and wattles become much paler and the blood- 

 vessels beneath the wing also look pale. The head apjiendages 

 gradually become more and moi'e pale as the di.sease progresses 

 and finally accpiire a pecvdiar bluish tinge. This tint also is 

 shown by the eyelids and ears and the legs are afiecteil though to 

 a. less extent. The feathers on the head tend to fall ott" so that 

 the forepart of the head and the region round the bill become 

 almost bald, and the bii-d presents a very peculiar ai)pearance. 

 owing to the bluish coloration. Leg weakness was ])resent in 

 several cas?s. 



The plumage of the infected birds is aflected in regions other 

 than the head, and the cjuills are less rigid than in normal birds. 

 The feathering of the legs is ragged and the sheen on the neck 

 and tail-coverts is not so well developed, while the replacement 

 of nestling down by ordinary feathers is nuich I'etarded in diseased 

 birds. 



During the progress of coccidiosis the birds sometimes develop 

 nuich mucus and a very ofi'ensive '•l)reath,"a smell of sidphuretted 

 hydrogen being noticeable. Both sticky mucus and smell disappear 

 as a rule in a few days, but may recur. 



While bii-ds suffering from coccidiosis feed greedily, internal 

 digestive troubles occur and the fteces voided by the birds are very 

 fluid, the condition being that of diarrluea. The csecal droppings 

 are the more noticeable, and they contain mai.\y resistant cysts 

 (oocysts) (figs. 4-8) of C. avium, l^oth sportsmen and keepers 

 have noted that diarrhoea is a marked symptom of " grouse 

 disease." Examination of soft dro[)pings daily shows the relative 

 numbers of oocvsts present and may be a rough gauge of the 

 intensity of the infection *. In good health the caH-al droppings 

 are of firm consistency and olive-green to brown in colour. When 

 cocciiliosis is slight, the faeces becouie softer and brownish yellov/. 

 In acute cases the excrement is almost fiuid and the binls void 

 sulphur-yellow fteces with a heavy, fu'tid odour. Fatty matters 

 may be present in the ca^cal contents. 



A day or so before the death of the infected bird the slimy, 

 mucilaginous discharge recommences, ooze coming from the beak, 

 nares, ears and eyes. Examination of this li(puil by the mici-o- 

 scope shows the presence of oval coccidian oocysts (cf. PI. LXil. 

 fifs. 4-8), all of which show the characteristic cyst-wall within 

 which is a single nninucleate mass of protoplasm. The mucus 

 also contains some shed epithelial cells in which occasionally 

 ma(;ro- and micro-gametes may be found. The ooze from the 

 eyes and beak chieHy contains (liicv.sts which may be due to 

 regurgitation from the crop just before dcatli. However, it 



* It ."-iKml'l t'l' iiotcfl tliiit ill sfviTf cjisrs of ilunrleniil cocciiliosis, m('rozoitp> iii;iy 

 hr fftniul IVcr in tlic ?iit-i-oiiU'iit> iind Ik-crs of ititVitrd hinls w licii iif> i)oi_\>t> arc 

 pirsnit. 



