80 DISEASE IN WILD MAMMALS AND BIRDS 
heart weights (page 63) it will be found that three of 
them have values below that of the class in which they 
belong ; the Carnivora alone have a greater heart-to-body 
ratio than the average for its class Mammalia. Nor do 
these orders have any direct dietetic relationsliip. The 
expected longevity of these groups does not permit one 
to discover any reason for arterial changes except per- 
haps that they have a reasonably good viability under 
park conditions, and therefore many have a longer oppor- 
tunity to develop vascular disease. It so happens, 
however, that the first four groups are the most likely to 
suffer from gastrointestinal inflammation, of dietetic or 
bacterial origin. 
It is interesting, but not easily explicable that the 
orders of great activity. Primates and Passeres, are at 
the end of the list ; their food is very largely carbohydrate 
in character. Just why Lemures, Rodentia and ColumbsB 
should be missing is not quite clear, because orders of 
comparative habits and food are included. 
A review of the concomitant pathology reveals the 
fact that nephritis more often accompanies these proc- 
esses than any other single condition. Among the chronic 
infectious disease in the table is included chronic enter- 
itis ; this group falls well behind the renal diseases. The 
relatively small number of cases of valvulitis speaks 
rather against an active infectious origin of the vascu- 
lar lesions. 
Aneurysms. 
Aneurysms have been observed all over the world and 
in nearly all the larger orders. The London Garden has 
had an unusually large number to report, the most 
striking being that described by Seligman in the 1906 
Report of the Society, in a tiger thirteen years in cap- 
tivity which had fourteen sacculations from pea to plum 
size scattered along the aorta. Even with the number of 
cases on record and those collected here it would be 
