232 



as stated by some physiologists. The author questions the theory of 

 the detachment of the epithelium of the villi in each act of absorp- 

 tion, on the grounds that the presence of detached epithelium was 

 unfrequent in the whole course of his experiments ; that epithelium 

 is readily detached by manipulation ; that the continual reproduc- 

 tion of such a vast amount of cell-tissue must necessarily be accom- 

 panied by a vast expenditure of vital force ; and finally, that it is 

 not necessary, because fluids readily penetrate epithelial membranes. 



19. The passage of a given food through the whole length of the 

 intestinal canal may occupy a comparatively short time, especially 

 when the animal is fasting. In one experiment, where a pigeon 

 refused food until the faeces contained no visible debris of previous 

 food, starch -granules were detected in the faeces within two hours 

 after a meal, and this although the intestine of this animal is ex- 

 tremely narrow and about a yard in length. 



20. A remarkable circumstance in the digestion of starch or 

 starch foods is the constant presence of myriads of vibriones in the 

 lower part of the intestinal canal. They are generally first observed 

 in the lower part of the small intestine, as minute brilliant points, 

 just visible with a power of 600 diameters, in active move- 

 ment. They increase in numbers towards the caecum, in which a 

 large number of fully- developed vibriones are constantly seen. 

 These minute organisms increase in size and length in the colon 

 and rectum, and their fissiparous mode of propagation, first described 

 by the author in the ' Quarterly Journal of Microscopical Science,' 

 may be distinctly traced by examining the contents of these por- 

 tions of the intestine. 



