THE VILLI. 67 



comb depressions which were described by Sir E. Home.* 

 When we examine an oblique or perpendicular cut of the mem- 

 brane under a simple microscope, we observe thousands of these 

 papilla projecting up from the surface of the membrane. ^The 

 honey-comb depression between these papillae according to the 

 observations of Dr. Boehm,f and Dr. Sprott Boyd,J are com- 

 posed of many tubular follicles, placed perpendicularly in the 

 membrane, and which open into the surface of the cell. The 

 diameter of these cells, according to Dr. Boyd, varied from 

 ^th to the 5 ^ th part of an inch. The bases of these follicles 

 rest upon the cellular coat of the stomach, and are considered 

 by Dr. Boehm, as similar to the tubular follicles of the large 

 intestines. (See fig. 140, page 71.) 



The villous or papillary prominences of the mucous mem- 

 branes are found in much greater number in the small intes- 

 tines than in any other part of the alimentary canal. They 

 were first discovered by Fallopius. They occupy the whole 

 length of the small intestines ; studding the valvuls conni- 

 ventes, as well as the spaces between them. Their number 

 is very considerable : Lieherkuhn estimated them at 500,000. 

 Some of the German anatomists, have more recently made 



* Sir E. Home described these honey-comb depressions as existing only in 

 the left extremity of the stomach, and considered the remaining portion of the 

 stomach occupied by the villi. Careful inspection, as Cruveilhier has observed, 

 will show, that the whole surface of the membrane is constructed alike in this 

 respect, with the exception, that the nipple-like or mammelonnated projections, 

 are more fully developed on the side of the pylorus, than at the cardiac extremity 

 of the stomach. A good idea of the appearance of the papillae of the stomach 

 when examined by the microscope, may be formed from an inspection of the 

 papillae villosae of the tongue, between the bases of which we are to consider 

 placed the honey-comb depressions. 



Ruysh has divided the villous prominences of the gastric mucous membrane 

 into two classes, papilla and villi, in which he has been followed by some anato- 

 mists : hence the gastric mucous membrane has been called the villoso-papillary, 

 But this distinction does not appear to be well founded. Careful observation 

 with the microscope, does not enable us to perceive any difference between 

 them, and they have heretofore been called indifferently, villi or papillae, and 

 considered as the representatives in the mucous membranes of the papillae of 

 the skin. P. 



f De Gland. Intes. Struct. Penit. Berol, 1835. p. 



\ Essay on the structure of the mucous membrane of the stomach. Edin- 

 burgh, 1836. P. 



