GROUSE DISEASE 573 



grouse may be the second host of H. microps is well worth 

 following up. 



It is curious to note that this tape-worm disappears during 

 the winter months, a fact which may afford some hint as to 

 its second host. The large tape-worms, on the other hand, 

 remain all the year round and must be of quick growth, for 

 they are found 35 cm. in length in a young grouse but three 

 weeks old. 



Three other round-worms have also been shown to exist 

 in the grouse. One of these in the duodenum may prove of 

 importance. This species {Trichosoma longicollc) is allied to 

 a form which lives in the human appendix and at times is 

 the cause of appendicitis. 



CocciDiosis 



Besides the worms we have in the grouse seven distinct 

 unicellular or protozoan parasites which live in the intestines 

 or in the blood of the 'grouse. Most of these are uncommon 

 and comparatively harmless, but one, a Coccidium (there is 

 no more popular word for it), is the cause of disease in the 

 grouse chicks. 



Since this disease was first found in the young grouse 

 much has been written about it in the newspapers and in 

 nearly every case the writer has taken the Coccidium to be 

 a Coccus. Now a Coccus is no more like a Coccidium than a 

 crocus is like a crocodile. The Coccus is a bacterium, a 

 vegetable and it has a simple life-history, the Coccidium is 

 a protozoan, an animal with as we shall see a very complicated 

 life-history. 



Dealing first with the Coccidiosis : 



One of the aims of grouse-preservers is to have numbers 

 of healthy young grouse chicks in order to produce stocks of 

 strong birds. Bad seasons for grouse are partly due to 

 epizootics among the young broods in the spring and the 

 chief cause of mortality among grouse chicks is a small, one- 

 celled microscopic animal parasite, Eimcria {Coccidium^ avium. 

 This parasite penetrates the lining membrane of the gut of 

 the bird and gradually destroys it, thereby setting up digestive 

 troubles in the form of intestinal inflammation (enteritis), accom- 

 panied by acute diarrhoea, which usually terminates fatally. 

 Grouse chicks are most susceptible to Coccidiosis during the 



