1876.] Anatomy of the Alimentary Canal. 243 



of the villus and that of the lymphatic follicles, there are considerable 

 differences between the cells of a lymphatic follicle and those of the villi. 

 In the villi the cells are polygonal, with oval nuclei and faintly granular 

 protoplasm ; the cells are arranged as an endothelium, and can hardly be 

 distinguished from the endothelial cells of the membrana propria, of the 

 blood-vessels, and of the lymphatics. A gradual transition is found 

 from the spherical lymph-corpuscles of the lymphatic follicles to the 

 polygonal cells (connective-tissue corpuscles) of the upper part of the 

 villi. 



It is found that there are more lymph-corpuscles in the villi of some 

 animals than in those of others. 



The author concludes that " the mucous membrane of the intestine is 

 pervaded everywhere by a reticulum, similar to and continuous with that 

 found in the lymphatic follicles of Peyer's patches. This reticulum is 

 situated among all the other elements which are contained in its meshes. 

 This is true of the epithelial cells, the muscle-fibres, the cells of the 

 parenchyma, the endothelial plates of the membrana propria, of the blood- 

 vessels, and of the lymphatics." 



9. Eat-absorption by the reticulum — (a) by the reticulum between 

 the epithelial cells. — The fat is seen to be arranged in lines between the 

 individual cells on viewing the epithelium from above. The separate 

 cells in teased preparations appear to contain fat j but it is considered 

 that this appearance is due to the fat-particles in the attached threads of 

 reticulum. 



The paper then relates the different situations in which this reticulum 

 has been seen (as in the salivary glands, rete Malpighii of the skin, 

 serous membranes, epithelium of the respiratory tract, &c), with the 

 different views which various authors have held concerning it. 



(b) Fat-absorption by the reticulum of the villus. — During absorption fat 

 is found to travel by the reticulum. 



Chapter II. gives an account of the minute anatomy of the pyloric end 

 of the stomach. This chapter commences by a short history of previous 

 researches, then follows a description of the minute structure. The 

 following are the results obtained : — , 



1. The surface is seen to present somewhat parallel folds ; the 

 stomach-tubes opening on the summits of these folds are longer than 

 those which open in the depressions between the folds. 



2. The epithelium is described as being closed during inanition, but 

 open at its free extremity during secretion. 



3. The germination of the epithelium is next described. The con- 

 clusions arrived at are : — that the epithelial cells divide ; that the small 

 rounded cells (other than the lymph-corpuscles) are the products of their 

 division ; that these small cells, increasing in size, rise up among the 

 older cells, push them to one side and become short broad cells ; that the 



