XC vi PROCEEDINGS. 



liver through the bile duct into the intestines, whence they ultimately 

 reach the ground. The eggs would all die if they did not fall upon 

 the earth during cold weather, when at the end of two or three weeks 

 they may be found as minute ciliated specks swimming in the water 

 of pools or rain puddles. These all die in ten hours if they do not 

 find a certain species of water snail, Limncea truncatula. Those which 

 find the snail stick to it, burrow into it, and soon become enc) r sted in 

 a small round cell. After some time it grows and changes into a 

 minute somewhat worm-like shape, bores through the cyst wall and 

 enters the liver of the snail. It is now called a Redia, and it produces 

 a number of offspring with a large head and slender tail called Cer- 

 carise which escape into the water of the pond. They finally swim to 

 land and climb up grass blades where they become encysted. They 

 die here in a short time unless a sheep comes along and swallows the 

 Cercaria with the grass. From the stomach of the sheep it enters the 

 liver by the bile duct, thus producing the disease from which the sheep 

 dies. The same animal appears in many different forms. First the 

 parasite embedded in the liver ; second, the ciliated microscopic pin- 

 head swimming in the water ; third, the cyst in the muscle of the 

 snail ; fourth, numerous Redire migrating to the liver of the snail ; 

 fifth, numerous Cercarise migrating from the liver of the snail into the 

 water ; sixth, the swimming Cercariie climbing the grass blades and 

 becoming encysted, covered with a tough skin making them look 

 like seed or scale stuck on the blade. Let the season be hot and dry 

 at the critical stage and the Liver-rot becomes extinct for the season. 

 In a few years if the climate is suitable they may become numerous 

 again. But if the water in the sheep's pasturage should be kept clear 

 of the said species of snail, no condition of climate could keep the 

 plague in existence. The extirpation of the snail is no easy matter, 

 and the Fluke is more destructive to sheep in Great Britain than the 

 Boer war is to the sheep in Africa at least a million per annum 

 dying from this cause. 



MARINE BIOLOGICAL STATION. 



We have been favored this year with the Marine Biological Station 

 of Canada at Can so. There, several of the scientists of Central Can- 

 ada were studying the inhabitants of our neighboring sea water, etc., 

 a knowledge of which will very soon be essential in order to preserve 

 some of our fisheries. The duties of my office have been so engross- 



