320 
SURGERY AND TRANSPLANTATION 
ness. African green monkeys (Cercopithecus 
aethiops) have been imported in large numbers 
to supply kidneys for tissue culture particularly 
for production of poliomyelitis vaccine, although 
this animal was the carrier of a virus M^hich 
caused the "Marburg" epidemic. That event 
highlighted a real risk in working with pri- 
mates and resulted, in Europe, in restrictions 
on importation of vervets. This undoubtedly 
contributed to the recent release of vaccines 
produced in diploid human cell cultures. 
Baboons are becoming increasingly popular 
wherever surgical procedures are involved and 
especially in experimental surgery as applicable 
to man. They are large, hardy, adapt to labora- 
tory caging and relate well to their handlers. 
Although large and potentially dangerous, they 
are less aggressive than rhesus monkeys and 
with proper precautions they can be used as 
readily as dogs. In five years of daily work with 
a colony averaging 150 baboons, only one tech- 
nician has sustained a bite which required 
medical care. This record of safety is the result 
of individual housing in squeeze-back cages, 
routine use of phencyclidine hydrochloride* for 
tranquilization when the animals are handled, 
and strict discipline and careful instruction of 
the staff. 
Baboons are intelligent and docile enough to 
be trained for maintenance in chaired experi- 
ments for many weeks. They may be housed 
easily and feeding and husbandry are not diffi- 
cult. 
Taxonomic classification of the baboons has 
been the topic of some controversy but we have 
chosen to follow Napier and Napier ^3 in this 
and all other taxonomic questions. While the 
baboon may not be quite as "close to man" as 
the anthropoid apes, practical considerations of 
availability, price, maintenance costs and fa- 
cilities make baboons the most valuable general 
purpose primate animal especially for experi- 
mental surgery. Its cousins, the drill, mandrill 
(Mandrillus sp.) and gelada (Theropithicus 
gelada) are too scarce ever to become regular 
laboratory species but the gelada is available 
for special studies such as xenografting of 
organs. 
* Sernylan, Bio-ceutic Laboratories, Inc., St. Joseph, Missouri, 
64502. 
The anthropoid apes (Table II) include the 
genera Pan (chimpanzee), Gorilla, Pongo, 
(orangutan), and Hylobates (gibbon). Gorillas 
and orangs are being depleted in their native 
habitats and are potentially in danger of extinc- 
tion. This, their large size, and difficulties in 
husbandry make them unsuitable for experi- 
mental purposes. However, small numbers are 
available in zoological collections; and in one 
of the primate centers, these have been used for 
significant phylogenetic observations. 
Gibbons (Hylobates sp.) are found in Ma- 
layan jungles but they adapt well to laboratory 
conditions and have been used in studies of 
virus infections, gastrointestinal observations 
and phylogenetic studies of blood grouping and 
serum proteins. They are small and fragile and 
are not useful as experimental subjects. 
Chimpanzees (Pan troglodytes) are potentially 
immensely valuable because they are, over all, 
immunologically and physiologically closest to 
man. They share human blood groups, are sus- 
ceptible to human viruses and are unique among 
animals in their susceptibility to hepatitis virus 
and streptococci. Chimpanzee organs have been 
transplanted to human patients and have sus- 
tained human life for periods up to nine months. 
Unfortunately, the growth of human popula- 
tions and economy in Africa is rapidly intruding 
upon chimpanzee habitats and constitute a 
rapidly growing threat to their survival. Pres- 
ently there are about 400 animals available for 
medical research throughout the world and one 
of the largest groups (71) is in the Laboratory 
for Experimental Medicine and Surgery in Pri- 
mates (LEMSIP) in New York. 
The use of our chimpanzee colony for experi- 
mentation is supervised by a Utilization Com- 
mittee which considers their threatened status 
before committing them to experimental proto- 
cols. We strongly recommend this careful re- 
gard for the future supply of chimpanzees and 
have been breeding our own animals as rapidly 
as possible. We have had three babies from four 
newly matured pairs during the last year. Large 
scale breeding of chimpanzees should be among 
our high priority national projects, but un- 
fortunately, no such program has yet been 
funded. 
