xevl 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, Limnea truncatula. Those which 
find the snail stick to it, burrow into it, and soon become encysted 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- 
carize 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 Redie migrating to the liver of the snail ; 
fifth, numerous Cercariz migrating from the liver of the snail into the 
water ; sixth, the swimming Cercarie 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 Canso. 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- 
