REVIEWS. 
409 
that Leuckart first fully described its mode of genesis and development, and 
lastly, that Zenker first showed that the ingestion of the worm gives rise to 
a series of very fatal symptoms — in fact, to a disease. 
The great bulk of Dr. Cobbold’s supplement embraces his account of a 
multitude of experiments made with different entozoa, with a view to dis- 
cover the effects both as to the development of the particular parasite and 
as to the position in the animal tissues in which it becomes lodged ; those 
on the Trichina being of most importance, both from the grave character of 
Trichiniasis, and from the fact that the results were on the whole very con- 
clusive. But there is also much information of a general character in regard 
to other entozoal points, and especially in reference to the peculiar gregarinida 
or psorospermiae foimd in cattle killed by cattle plague, and which were, at 
the time of the Einderpest invasion, described and figured in these pages by • 
Dr. Lionel Beale. 
The chapter which the philosophic naturalist will read with most plea- 
sure, is the last one, in which Dr. Cobbold expresses his views on the ques- 
tion of organic individuality from an entozoal stand-point. Those who 
have read Dr. Quatrefages’ charming work on the Metamorphoses of Man 
and the Lower Animals,” * will remember that the whole of the phases 
which an animal presents from the period of leaving the ovum (or, as Van 
Beneden and Sars have shown, even before leaving the egg) till it has 
arrived at sexual maturity, must be included within the term individual. 
They are all, in fact, but one being, the different stages being technically 
styled zooids. Now different methods of classification have been adopted for 
the purpose of conveniently grouping these stages together to the framing of 
certain analogies, more fanciful than real. Dr. Cobbold strikes out a new 
path, and proposes a novel or somewhat novel mode of arranging the develop- 
mental phases of Entozoa. His plan is simple, and has doubtless certain 
advantages, but we dissent from it simply on the principle that all such 
methods of grouping are valueless in so far as the extension of philosophy 
is concerned, and have only this one merit, that of being methodic. Let us, 
however, place Dr. Cobbold’s scheme briefly before our readers, and allow 
them to judge for themselves. It is proposed by the author to call each 
successive life-epoch in the history of an entozoan, whether it be distinc- 
tive or indistinctive, separable or inseparable,” a biotome. Eurther, when 
there are more than one of such biotomes, he distinguishes them by the 
terms primary, secondary, tertiary, &c. Taking T(e?iia serrata as an example, 
we get the following plan : — 
Zoological individual (T. serrata) 
a Ovum in all its stages 
h Six-hooked larva or pro-scolex 
c Besting larva scolex or cysticerciis pisiformis 
d Sexually immature tape-worm in all stages 
e Mature tape-worm colony, strobile or 
T<^nia 
f Segment, free-joint, or proglottis (Zooid) . 
Primary Biotome. 
Secondary Biotome. 
Published by Hardwicke. 
