THE ALIMENTARY CANAL AND ITS APPENDAGES 169 
with accompanying very decidedly retrogressive changes (patho- 
logical cases excluded) in the related tissues.’ 
Taking only adults into consideration (ze. omitting individuals under 
twenty years of age in whom variations are comparatively rare), out of 100 
vermiform processes 32 were found partially or wholly closed. Complete 
occlusion throughout the whole organ was fonnd in a very small number, 
about 34 per cent. Partial occlusion is much more frequent, all degrees 
being found, from the first narrowing to the complete closing of the lumen. 
Fic. 101.—THE Ca@cUM AND VERMIFORM PROCESS IN A KANGAROO. 
i.l., large intestine ; 7.s., small intestine, v.7.c., position of the ileo-colic valve ; ce., 
coecum. 
In rather more than half of the cases the occlusion affected a quarter of the 
length ; in nearly half of the remainder its extent varied between one 
quarter and three quarters, and in only a very small number did it affect 
more than three quarters, or close up the tube. 
This process of occlusion is equally marked in both sexes, 
and the statistics concerning its occurrence at different ages are 
very striking. They make it clear that there is marked increase 
' Actual pathological obliteration, nevertheless, occasionally occurs at the end of 
the vermiform process, 
The occlusions which result, and which are probably always due to inflammation, 
are less frequent than the typical obliteration (Ribbert). 
I cannot again in this connection refrain from referring to the coincidence of the 
existence of vestigial organs and the tendency to disease caused by them. 
