616 DISEASE IN WILD MAMMALS AND BIRDS 
ization. At any rate the time has arrived to establish 
at least a nucleus for the accretion of data, which can be 
later subjected to confirmation or correction. We draw 
just a grain of comfort from the knowledge that the more 
fully worked field of human parasitology is also vulner- 
able to criticism of very much the same order. 
The Value of Parasitological Studies in Zoological 
Gardens. 
The foregoing chapters have made clear two fields 
of practical usefulness of any study in such gardens. 
These — hygiene in relation to the animals and comparison 
in relation to human beings — need therefore only to be 
mentioned at present since it is ob\4ous that both benefit 
by our parasitolog-ical work. But there is yet a third — 
a scientific phase of parasitology which may be considered 
purely academic. It consists in morphological and other 
studies necessaiy for the identification of the parasite, 
the determination of its life history, etc. These last 
studies may still in a restricted sense include a modicum 
of the practical in so far as they have a bearing on the 
disease with which they are associated. But on the whole 
they are a source of danger for us since such things 
as studies on the finer structures of worms, taxonomic 
arrangements, descriptions of new species of commensals, 
etc., being alluring, are likely to lead one so far afield that 
eventually an attitude of stubborn resistance will have to 
be assumed in order to conserve that precious, volatile 
laboratory asset — time — for the more crying, practical 
problems ever reaching out to us. 
However, in parasitological investigations as in other 
scientific work, immediate abstract information may at 
some time prove to be of greatest practical value. Thus 
for example if we can discover the exact facts concerning 
one phase of the life history of a certain parasite, it may 
be possible by hygienic measures, to break the cycle of 
development of the parasite at one point thereby prevent- 
