COBBOLD, ON ENTOZOA. AB, 
is undoubted, both being part of a series of changes under- 
gone by a living being in the cycle of its existence; and Dr. 
Lawson’s objection to the statement, that “ vital operations 
are not to be explained by a reference to the known laws of 
force,” is certainly trivial and unnecessary. Can Dr. Lawson 
explain vital phenomena by any of the known laws of force ? 
We think not; those laws, whose existence is undoubted, 
which come into play, in the fecundation of the ovum, in the 
appropriation of nutriment resulting in growth, and such 
phenomena, are at present, though possibly not for many 
years, unknown. At any rate, these phenomena never have 
been explained by any known laws; and the high branch of 
organic chemistry which their study constitutes forms one 
of the most important fields of labour for the physiological 
chemist. 
Entozoa.—dn Introduction to the Study of Helminthology, 
with reference more particularly to the Internal Parasites 
of Man. By T. Srencrur Cosporp, M.D., F.R.S. 
Or all possible subjects, perhaps the last that one would 
expect to see treated in a book having the appearance of 
being “ got up” more to lie on the table in the drawing- 
room than in the study, is that of Helminthology. However 
unjust its claims, it cannot be denied that the study of the 
life-history of internal parasitic animals is by no means one 
which offers attractions to the popular mind, which is always 
so prone to content itself with the contemplation of the out- 
sides of things, and, moreover, so apt to be disgusted with 
any reference to what may be taking place in the interior of 
the animal body. 
Within the outer and visible animal world, however, there 
is another for the most part concealed from view, and in some 
cases almost invisible to the unaided sight even when sought 
for, but whose existence is rendered but too manifest by its 
noxious or even fatal effects. But it is a world equally worthy 
of study with the exterior, and which in fact affords peculiar 
phenomena amongst the most remarkable in the whole 
organized creation. Scarcely any animal, from the lowest 
protozoan to the highest mammal, is exempt from the liability 
of becoming the involuntary Amphitogon to unbidden para- 
sitic guests, which ave in many cases destructive to the life of 
