217 
of the Oviviviparous Shark y &c. 
vivifying principle in all classes of animals ; and that it is not 
simply applied to the blood, but mixed with that fluid while 
circulating in the arteries, since, if this were not the case, 
there would be no means of aerating the foetal blood in the 
higher orders of animals. 
Experiments on the Jelly formed in the Oviduct of the Frog , and 
Oviviviparous Shark , by Mr. W. Brande, F.R.S. 
The substance contained in the oviduct of the frog, is of a 
whitish colour, nearly opaque and extremely viscid. It does 
not mix with water, but at common temperatures expands 
slowly in that fluid to about twelve times its original bulk. 
At a temperature of loo 3 , this expansion is much more con- 
siderable, and the substance puts on the appearance of an 
attenuated and nearly transparent jelly, but none of it is 
dissolved. 
The expansion seems to depend on the absorption of 
water by the gelatinous substance, the proportion of water 
taken up being very great. A piece of the unexpanded sub- 
stance of the size of a large pea, requires rather less than 
three ounces of water for its complete expansion, and a mass 
of jelly equal in bulk to three ounces is formed. 
This substance dried at a temperature of 212 0 , becomes 
brittle, but when it is put in this state, into moderately warm 
water, it again expands, becoming nearly as bulky as before. 
Digested in alcohol it becomes brittle and opaque, and con- 
tracts to about one half of its original bulk. If in this con- 
tracted and perfectly brittle state, it be put into warm water, 
it again expands as before. But when once expanded, it is 
neither hardened nor coagulated by alcohoh 
