AMERICAN INSTITUTE. 481 



respiration, M. Dutrochel had explained well how the ascent of 

 sap, its exposure, and that of the blood in the animated tribes was 

 a matter of transudation. If dark nervous blood were exposed 

 to the air through the bladder which might contain a portion of 

 it, oxygen would soon be absorbed from the air, and the scarlet 

 tinge observable. The Doctor made a little experiment with 

 solution of iodide of potassium and acetate of lead, which were 

 made to communicate through a bit of Chamois leather, the double 

 decomposition being almost instantaneously observable. He then 

 explained and demonstrated the circulation in fish as single, in 

 contradistinction to that of the double-hearted mammalia, who 

 have lungs. He described the air bladder and its uses. Fish 

 make nests, like their cousins the birds. He explained the pecu- 

 liarities of the mode of the fecundation of oviparous and vivipa- 

 rous animals. 



Mr. Field wished there were more fish to eat up the mosquitoes. 



Dr. Waterbury proceeded to demonstrate the double jointed 

 arrangement of the fish's back bone. You, said he, and I were 

 once fish, at least we lived the lives of fish, we breathed as do 

 fish. He explained tlie peculiarity in the silver eel which 

 causes the fishmongers to imagine he is a snake and destitute 

 of gills. It merely is that they are covered externally by a 

 delicate membrane, and with a little water in his mouth he can 

 live for a short time on the grass of a wet meadow. Fishes are 

 the oldest living inhabitants of the globe. Fish with one lobed 

 tails had become imbedded in the red sandstone, and existed upon 

 the earth long before any other creature E:ade a noise. As a 

 class, fish compose nine-tenths of the animal world. What did 

 the shad live upon ? It was a curious enquiry. And why did he 

 regularly go up the North river ? 



Dr. Waterbury presented a dissected codfish, to illustrate a 

 drawing upon the blackboard, showing how a fish lives upon 

 wiiat the fishermen calls " suction" — a sucking in of air and wa- 

 ter, highly charged with oxygen. He also illustrated the fact 

 that fish have hearts, and showed where they were situated, at 

 the base of the gills. 



[Am, Inst.] 31 



