208 THE GROUSE IN HEALTH AND IN DISEASE 



Specimens of T. pergracilis are found in the caeca of most 

 Grouse. They have been found, with hardly an exception, 

 in every one of the two thousand Grouse examined by the 

 Committee. They are apt to cover themselves with mucus 

 and dirt, and are consequently hard to see, and are often over- 

 looked. But they may be rendered opaque and white, and 

 hence much more apparent, by shaking up the contents of the 

 caecum in 75 per cent, alcohol, to which a few drops of corrosive 

 sublimate have been added. Their presence is also readily 

 detected by compressing a drop or two of the caecal contents 

 between two microscope slides and holding them up to the 

 light. The worms, if there be any, then appear as thin, white, 

 transparent lines. 



A small pellet of the caecal contents, such as can be carried 

 away on the point of a needle, when spread out under a 

 coverslip, will, in a well-infected bird, show some twelve to 

 twenty worms and one hundred to two hundred eggs in the 

 field of a two -thirds inch Ross's objective with a No. 2 

 eyepiece. 



For the purpose of ascertaining the exact numbers of this 

 worm in a single specimen a method of isolating and counting 

 them has been devised and found to be practicable. The method 

 is as follows : The caeca are laid out straight on a board and 

 opened throughout their length, their contents are turned out. 

 and all the material liable to contain Strongyli is collected. 

 Small quantities are shaken up with water in a large test-tube, 

 and poured out little by little into a Petri dish containing water. 

 With suitable illumination the Strongyli can be clearly seen 

 and picked out with a mounted needle and counted. As may 

 be seen, by reference to Table L, in all but two birds (Nos. 57 

 and 67) approximately equal numbers of the worms are present 

 in each of the two caeca. 



Strongyli are almost constantly present in the caeca of wild 

 Grouse believed to be perfectly normal, and certainly of fair 

 weight and in good general condition. In a few so-called 

 healthy birds they may be present literally in thousands, 



