4 
INTRODUCTION 
what from the context in which most of us have 
generally used the term. A model, as the diction- 
ary would define it, is a small copy, an imitation 
or a preliminary representation which serves 
as the plan from which a final larger object is 
constructed or formulated. A model then is in- 
tended to be copied or followed. I point this out 
because it is at variance with the common 
practice in animal research. Most animal models 
are not, in fact, an accurate representation of 
the larger object, which in most cases is man. 
I can put it another way and more bluntly, that 
a staggering amount of medical research is ac- 
complished on inappropriate models. This has 
been responsible for an enormous duplication 
of efi'ort, confusion of results and often plain 
misunderstandings. 
For example, in cardiovascular research, con- 
sider that the animal which has attracted 
the most effort and has been studied in the 
greatest depth in research related to the cardio- 
vascular systems is the mongrel dog. It would 
be inappropriate for me to demean the contri- 
bution which studies on the dog have made to 
our overall fund of knowledge, but I think it is 
entirely appropriate to point out that there has 
been an amazingly small effort to determine 
the validity of the dog's cardiovascular system 
as a model for that of man. The dog came to 
occupy its present prominent position due to 
largely nonscientific reasons. The mongrel dog 
is available, cheap, convenient, and tractable, 
and I suppose that it continues to be used 
for all of these reasons. But tractability, 
cheapness, availability and convenience are 
really not bona fide criteria for selection of a 
model. Other, more appropriate models do exist, 
but many investigators have been unwilling 
to look beyond the dog. I see a need to break 
away from the tendency to use as models only 
those species which have historically enjoyed 
popularity, and to look to other models ; — 
higher and lower species, large and small ani- 
mals; primates, and even exotic species. 
One of the stated objectives of the conference 
was to acquaint members of the research com- 
munity with new or different models, particu- 
larly large animal species or primates. This 
books contains many papers on the physiology, 
care, surgical approach, behavior, and use of an 
interesting variety of potential subjects. Many 
researchers are unaware of the potential that is 
offered by some of these species. They also 
appear to be unaware that many volumes have 
been written and that many conferences like 
this have been held which have focused on in- 
dividual animal species. 
The laboratory pig, for example, offers re- 
searchers an excellent experimental model of 
the human skin and cardiovascular system. 
There is voluminous literature available on the 
pig including a definitive volume. The Stvine in 
Medical Research, which was based on a meet- 
ing like this and which has a great deal of basic 
data in it. But similar data also exist in similar 
volumes compiled on a number of other animals : 
primate species, bovine and equine species, 
many of the lower forms, fishes and so forth, 
even polar bears and giraffes. 
The advantages inherent in primates as mod- 
els of man are obvious, but researchers have 
been quite slow to capitalize on this particular 
opportunity. Primates should no longer be 
looked at as exotic animals that are expensive 
to acquire, difficult to manage, and about which 
very little is known. The advent of the original 
primate research centers which are sponsored 
by the National Heart Institute has altered that 
image. A great variety of primates is available 
in the centers throughout this country. Their 
cost now compares very favorably with the cost 
of conditioned laboratory dogs, for example. 
The means of managing and handling the var- 
ious primate species have been developed and a 
superb data base exists on all of the primate 
species. Beyond that, a primate information 
center, maintained as a national service, has a 
computer bibliographic data retrieval system 
service which is available and will provide 
practically instantaneous print-outs of the 
world literature on any primate-related subject. 
I don't think that is the case for any other 
experimental animal. 
The fact that certain of the primate species 
have been numbered among the endangered spe- 
cies has been anticipated and breeding colonies 
have been established. Not only have these 
proved to be successful enterprises in terms of 
increasing the absolute numbers of primates 
available, but they have also attracted the in- 
