THE ANIMAL PARASITES 625 
belongs, etc., and then compare these verminous properties 
with those of the host — its size, temperament, physical 
stamina, etc. This tliird consideration must necessarily 
overlap with or be supplementary to the first two. For 
example, this consideration would have to be resorted to 
in many cases of ascaris infestment where anatomical 
changes are generally not demonstrable. 
Acting on these three considerations, and after twelve 
years of observation on parasites here in the Garden, a 
fresh review of our records, and a recent review of the 
accessible relevant parasitological literature I have come 
to the conclusion that, considering wild animal collections 
the world over, there is no justification for an unqualified, 
definite answer to the question of pathogenic parasitism 
that will meet all conditions. We lack data on too many 
species that are not sufiiciently represented in collections 
or indeed not represented at all. It is the liability to 
infestment of each order or family of beasts that will have 
to be determined, and, depending on the assortment each 
garden has on exhibition, will the importance of parasites 
to the garden as a whole vary. 
Speaking for the Philadelphia Garden, I have come to 
the conclusion that on the whole parasitism does play an 
important part of our animal losses. The financial loss 
which could be charged against spiroptera alone is in the 
four figures, to say nothing of the difficulty of replace- 
ment of rare species. And while touching the financial 
phase let it be added that scientific work done now, it must 
be remembered, is not restricted to the present time or 
place, but is to be measured in dollars and cents with the 
yard stick applied to the future, and in other places than 
that where the initial work is done. Even if we cannot 
answer the question of the matter of importance the world 
over we can guarantee that it is sufficiently so in the 
Philadelphia and London Gardens to warrant a rigid 
supervision for parasitism; and since the other larger 
collections are probably made up of similar animals, 
