67 



the experiment. At the same time, the secretion of the 

 substance from the walls of the sac ceases, and the remains 

 of the style are pushed into the stomach by the action of 

 the cilia. 



Barrois' own view, based chiefly on the chemical 

 composition of the style, is that it is a cuticular structure 

 secreted by the wall of the sac, which acts as a lubricating 

 material and invests sharp particles of sand. Sec, with a 

 viscous coating which prevents damage to the intestinal 

 wall. As it is formed it is moved forward into the cavity 

 of the stomach, where its free extremity is continually 

 being worn away by the attrition of the food particles and 

 the solvent action of the digestive fluids. The viscous 

 fluid so formed also unites the food matter into a coherent 

 bolus which easily traverses the intestine. 



The view that the style is a cuticular structure secreted 

 by the wall of the pyloric caecum seems rather difficult to 

 reconcile with the appearance of that epithelium, for, 

 with the possible exception of the longitudinal strip of 

 elongated cells in the caecum, the wall of the latter does 

 not present the appearance usually associated with a 

 secretory surface. The compact layer of columnar cells, 

 the refractile free border, and the dense layer of long 

 stiff cilia contrast strikingly with the wall of the right 

 division of the lumen of the straight portion of the gut, 

 where secretion into the cavity of the intestine is most 

 probably taking place, and is far more suggestive of a 

 surface performing a mechanical function than of an 

 actively secreting epithelium. And it seems unnecessary 

 to locate the mucus-secreting epithelium in the wall of 

 the crystalline style sac. All along the course of the 

 intestine there is abundant evidence of some substance 

 being poured out into the lunien, in the rounded homo- 

 geneous bodies found in the wall or projecting from the 



