636 The Relations of the Diseases of Animals to those of Man. 
sary, in order that the mortality amongst patients and dogs that 
have the ill-fortune to get bitten may be diminished. As a pro- 
phylactic treatment the outcome of Galtier's labours can scarcely 
yet be looked upon as completely successful. 
At the same sitting Professor Brown gave an exceedingly inter- 
esting demonstration on " Animal Parasites," and Professor Railliet, 
of Alfort, gave an account of the "Parasites transmissible from 
Animals to Man," which, when published, should prove of extreme 
value to those who study medical or veterinary hygiene. 
Professor Brown, before his demonstration, referred to Sym- • 
biosis. Mutualism, Commensualism, and Parasitism, defining the 
different shades of meaning involved in each term. The .demon- 
stration included specimens of specially prepared and mounted 
parasitic organisms, and photographs, all of which were projected by 
means of a lime-light lantern on to a screen at the back of the hall. 
There were included beautiful examples of trematode worms ; the 
ordinary liver-fluke, both in the embryo state and in its adult 
form ; cestode worms ; various forms of tapeworms, with their 
developmental cystic stages, including the forms met with in 
the human subject, in dogs, sheep, &c. ; nematode worms, or 
round or thread worms, especially those forms found in the digestive 
canal and in muscles ; the whip-worm, the worm of trichinous 
pork, &c. ; and the Acanthocephalce, or thorn-headed worms. 
Professor Railliet, after dividing the parasites transmissible 
from animals to man into animal and vegetable, and 'external and 
internal, and the external parasites into temporary and stationary, 
said that the internal parasites were nearly all stationary. Some 
common to man and animals, or living more especially in animals, 
may develop accidentally in man {Trichina spiralis of measly 
pork). Others are compelled to penetrate into the organism 
of man in order to complete their life-history, so that they are 
usually transmitted direct {Tcenia solium, the common tapeworm). 
Indirect transmission may take place through the medium of food or 
water which animals have polluted or infected by depositing ova or 
embryos. Here two kinds were found — those in which the parasites, 
living in the adult state in animals, are capable of attaining the 
same state in man, as with the common liver-fluke ; and those 
which, living in an adult state in animals (Tcenia echinocqccus in 
the dog), only develop in the larval stage in the human subject 
(hydatid cysts). 
Direct transmission is brought about by the consumption of the 
flesh of infected animals, in which case the parasites living in the 
larval state in animals become developed into their adult form in 
man, as in the case of the tapeworms of measly pork and beef, and 
in the Trichina spiralis of trichinous pork. 
As to the means to be taken to prevent the spread of these 
parasites, we ought in the first instance to avoid contact with 
animals suffering from parasitic aflfections which we know to be 
transmissible to ourselves, <at the same time endeavouring to destroy 
the parasites and their progeny, not only in the animals themselves, 
but also in all parts which may have been affected. In the second 
