Vermiform Appendix. 351 



erratic feeders, the question arises whether the distortion seen in 

 the dog's caecum and in man's appendix are due to adhesions 

 contracted di^ring varying distentions of the digestive tract 

 which shift these organs into varying positions. 



Treves' type C is, perhaps, from an anatomical standpoint, 

 the least important of his types. It represents the com- 

 monest type found in man (the normal caecum of Deaver), and 

 thus assumes an importance on that account alone. It repre- 

 sents the migration of the appendix half way between the fundus 

 of the caecum and the ileo-caecal valve, a migration due to the 

 pull of the mesenteric muscle band. 



Treves' type D, also Fig. 16 and the caecum of the wombat 

 (Figs. 1 and 7) are alike. In each case the appendix opens on 

 or into the lower lip of the lieo-caecal valve, having been 

 dragged to that position by the pull of the mesenteric muscle 

 band. Under the pull of this band, atrophy on its side is estab- 

 lished earlier than on the free side, and the drag of the 

 mesenteric band is transmitted to the colon, which assumes a 

 position mimicing caecum when caecal atrophy Becomes extreme. 

 The caecum on the free side atrophies as the sphincteration of 

 the colon eases under the influence of diet of less bulk and 

 greater nutritive power. In the human caecum, variations of 

 type D occasion much confusion during surgical operations. These 

 confusing caeca have been under the influence of a preliminary 

 artophy which has subsequently been subjected to caecal disten- 

 sion. Fig. 1.3 shows this condition. The point of interest is 

 the U-shaped longitudinal band which offers clear evidence that 

 the colon has been drao-cred down either bv distension or this 

 force plus gravitation. 



We have examined a number of Victorian wombats' caeca. 

 (Figs. 1-14.) They all show Treves' D type caecum^ — ^the appen- 

 dix of a small size. A Avombat's caecum sent us by Mr. Desmond 

 /rom South Australia (Fig. 7) is also of Treves' type D ; its 

 appendix, however, is about three times the volume of the Vic- 

 torian's. Perhaps we have an abnormally big appendix from 

 South Australia ; perhaps food differences in the two States 

 explain the lesser ^trophy shown by the wombat of South 

 Australia. This is a point which should be cleared up. In a 

 paper published in the '' Australian Medical Journal " of 20th 



