414 Sckntyic Intelligence* — Physiology. 
of animal heat ; assimilation, the motion of the blood, the fric- 
tion of various parts, may produce the small remaining portion. 
2. Besides the oxygen employed in the production of carbonic 
acid, another portion of this gas, which is sometimes very con- 
siderable in proportion to the first, disappears ; it is supposed 
generally, that it is employed in the combustion of the hydro- 
gen of the blood. In general more oxygen disappears in the 
respiration of young animals than in that of adults. 3. Exha- 
lation of nitrogen takes place in the respiration of those mammi- 
ferous animals, which are carnivorous or frugivorous, and in the 
respiration of birds ; the quantity of nitrogen exhaled being 
greater in frugivorous than in carnivorous animals.-— de 
Chim.^ xxvi. 360. 
SO. Lizars on the Ovaria. — Mr Lizars, Lecturer on Anato- 
my and Surgery, is about to publish an account of his opera- 
tions in extracting morbid ovaria, which have been eminently 
successful. We have seen the beautiful drawings intended for 
Mr Lizars’s work. They represent the |^coloiirs, surface, and 
form of the ovaria ; but representations of internal structure 
ought also to be given. 
21. Seeing in Water. — In experiments made with the view 
of determining whether or not we can see under water, some in- 
dividuals maintained that they could see, while others, with 
equal confidence, asserted, that all around them was dark. In 
explanation of this seeming contradiction, it may be remarked, 
that in some individuals, owing to the delicacy of the conjunctiva 
and lachrymal gland, the eye remains shut when immersed in 
cold water ; others, whose eyes remain open, and who maintain 
that they see under water, actually do not see Xhe foi'ms qf ob- 
jects^ only the light reflected from bodies having a bright sur- 
face, as silver. The pearl fishers of antiquity are said to have 
used glasses of a particular kind, to enable them to see the pearl 
mussels. Instruments for seeing under water have been pro- 
posed by modern artists. 
CHEMISTRY. 
22. Presence of Mercury in Common Salt. — -Boyle, Stahl, 
Senac (Athanasius), Kircher, Glauber, and many other chemists, 
have presumed the existence of mercury in common salt. Hil 
