408 
EEVIEWS. 
EXTOZOA.* 
HE strides wliicli natural science makes from year to year are so vast 
that even in a small department like that of the study of Entozoa, it is 
found that what is written to-day, he it never so complete, will not he en 
rapport with the state of science two or three years hence. Dr. Cohhold, 
who a few years ago gave us his splendid monograph on the Entozoa, has 
realised this fact j and, in accordance with the wants of naturalists, he has 
issued a supplement to his former treatise in the volume now before us. But 
this new work has a value apart from its supplementary character. It con- 
tains a mass of very useful and interesting facts, which may be read quite dis- 
tinct from the earlier treatise. Of this nature is the author’s chapter on the 
history of the discovery of Trichina spiralis. Perhaps in the wEole of the re- 
cent history of internal parasites, there has been no creature which has been 
regarded with more interest or terror than the little flesh-worm which is called 
Trichina, and which threatened to do so much mischief among our Teutonic 
neighbours some time ago. This nematoid, which is to a certain extent 
microscopic, and which is to be found occasionally in myriads in pork, and 
even in the bodies of raw-poik-feeding human beings, is essentially a native 
of Germany. A'et, singularly enough, it was first discovered in this country. 
But the question who was its discoverer, was one which, while it excited 
much controversy, it was impossible to answer definitively, till Dr. Cobbold 
inquired into the matter, and gave us the decisive reply which his chapter 
on tlie subject expresses. The author has been at great pains to go through 
all the literature relating to the discovery of Trichina, and -we think his 
conclusions, which are formulated in nine separate propositions, may be 
ac'cepted as final. The first of these is that “ Mr. Paget first actually deter- 
mine<l the existence of the parasite, which was subsequently more com- 
pletely described by Prc»fes8or Owen. !Mr. Paget was assisted in the discovery 
by the celebrated botuni.st Pobert Brown, who lent his microscope for the 
purjwse of examination.” Tlie other “ conclusions ” state that Profe.«.sor 
Owen first scientifically described the worm, that ^Ir. Wormald supplied 
him with the specimen.s, that Mr. Hilton first suggested the parasitic char- 
acter of the worm, that I lerbst was the first to rear the worm experimentally, 
• “ Entozoa. Being a supplement to the Introduction to the Study of 
Helminthology.” By T. Spencer Cobbold, M.D., E B.S. London : Groom- 
bridge. 
