2i6 STUDIES IN INSECT LIFE, ETC. 

 of the grouse. When the birds harboured from 

 100-1,000 round-worms, bacilli occurred in the 

 tissues of about 50 per cent, of the birds bacilli 

 let out from the cavity of the intestine " by a 

 worm's pin-prick," to quote Browning's " Lovers' 

 Quarrel." When over 1,000 or more worms were 

 present, the bacilli, with one exception were 

 found in the liver and in other organs of the 

 body in 100 per cent, of the birds investigated. 

 The exact relation of these bacilli to the sickness 

 of the bird is still a matter of inquiry. It seems 

 as if they are soon absorbed, and that no specific 

 disease is traceable to them, but if they exist 

 in numbers their products must exert a harmful 

 influence. 



The existence of disease caused by the passage 

 of these bacilli through the walls of the alimentary 

 canal through lesions caused by tape-worms is 

 less well established than through the disorgani- 

 sation of the lining membrane of the caeca caused 

 by T. pergracilis. On the other hand, one must 

 not overlook the fact that Hymenolepis is especi- 

 ally numerous in the spring and autumn months, 

 during which the greatest mortality takes place, 

 and is absent during the winter when the birds 

 are comparatively healthy. 



