244 
POPULAR SCIENCE REVIEW. 
Academy requesting it to direct its Commissioners to examine, with the aid 
of the solar microscope, the animalcules to which she attributes the produc- 
tion of cholera, and specimens of which she offers to place at their disposal. 
The Accommodation-power of the Eye. — The manner in which the human 
eye alters its focus for the perception of objects at various distances has 
always been a difficult problem for physiologists and physicists. The litera- 
ture of medical science is full of dissertations on this subject, yet very little, 
if anything, is positively known of the exact means by which the alteration is 
achieved. There appears to be now a tendency among ophthalmologists to 
believe that the effect required is produced by an alteration of the form of 
the crystalline lens of the eye, which becomes less or more convex as occasion 
demands. This view has just received a rather strong condemnation by the 
Eev. Professor Haughton, of Trinity College, Dublin, in some remarks pub- 
lished in the Dublin Quarterly Journal of Science. Speaking of the altera- 
tion of form in the lens, he says : — “ Even this must take place on a far 
greater and more important scale than anatomists have as yet suspected. The 
change amounts to the addition of a double convex lens of crown glass 
having a radius of a third of an inch. Anatomists have not as yet discovered 
a mechanism for changing the shape of the lens sufficient to produce these 
results. The lens should almost be turned into a sphere, and I know of no 
ciliary muscles capable of effecting so great a change.” 
The Organization of the “ Cell.” — If we are to believe in the statements of 
M. Balbiani, a French naturalist of considerable repute, the function of the 
cell in animals is far more complex than is generally believed. M. Balbiani 
seems to support the cell theorists in their opinions, for he gives the cell and 
its nucleus peculiar vital powers. Cells, he says, have a vital individuality ; 
they manifest phenomena of movement and sensibility ; they are the seat of 
considerable nutritive activity, and the nucleus is the principal centre of this 
activity. The most extraordinary fact which M. Balbiani adduces is, that 
the phenomena exhibited by the nucleus are due to the presence of a series 
of canals like those of Infusoria, which serve for the distribution of liquids 
in the interior of the parenchyma. If this discovery be true, M. Balbiani has 
thrown a new light upon the subject of tissue development by establishing 
the existence of a circulation of fluids in the elementary parts of the 
organism. — Comptes Bendus, Dec. 26 . 
A Trichina Commission , consisting of M. Delpech, Professor of Medi- 
cine ; M. Raynal, Veterinarian ; and M. Alfort, has been sent by the French 
Minister of Agriculture to Germany, to examine and report upon the 
Trichina disease, prevalent in pork. 
The Structure of the Blood Globules. — In the Report of the Proceedings of 
the Royal Academy of Sciences, St. Petersburg, we find an essay upon the 
structure of the minute corpuscles which give colour to the blood. M. 
Ofsiannikof, the author of the memoir in question, states that in all cases the 
blood globules possess a distinct membranous wall, which is acted on differ- 
ently by different fluids, and which differs in its reaction from the nucleus 
and contents. The blood globules of the same animal are not alike. The 
contents of the corpuscle crystallize easily within the surrounding envelope. 
It is wrong to suppose that special fluids are required to alter the form of the 
blood globules, as these bodies change their outline even under the influence 
