Amoeboid cells in intestinal absorption, 15 



lymphatic glands. It is more of the nature of areolar tissue; with 

 flattened and branched cells, connective tissue fibres in variable amount 

 according to the kind of animal and tlie part of the intestine under ex- 

 amiaation, a large proportion of soft ground-substance , and a con- 

 siderable but variable number of cells wMch are quite like the white 

 corpuscles of the blood. It is bounded superficially next the epithelium 

 by a layer of flattened connective tissue cells, which are in some 

 animals branched and united by their processes, in others joined edge 

 to edge and then form a complete epithelioid covering or basement 

 membrane. Pervading this tissue is the network of blood capillaries 

 which approach close up to the basement membrane, wliile in each villus 

 the usually clavate lacteal runs along the centre with small bundles 

 of piain muscular tissue derived from the muscularis mucosae running 

 parallel to it on all sides. 



Undoubtedly the most striking feature of the mucous membrane, 

 particularly in mammals, is the large number of amoeboid cells wMch 

 it contains. They are found even between the epithelium cells, and 

 at intervals cells essentially similar but of smaller size occur massed 

 together to form the lymphoid nodules known as solitary glands and 

 Peyer's patches. These structures are universally credited with the 

 function of producing lymphoid cells, of which indeed they are cMefly 

 composed; and there is little reason to doubt the correctness of this 

 belief. ^) But no one so far as I am aware has endeavoured to explain 

 why there should be such a special accumulation of these cells along 

 the alimentary tract and especially towards the lower end of the 

 small intestine. If however they are actively concerned in promot- 

 ing the absorption of the products of digestion their presence here 

 becomes easily intelligible. 



As above stated lymph- corpuscles are found in the epithelium 

 between the columnar cells, where they may approach quite close to 

 the free surface.'^) They are decidedly amoeboid, but whether they 



') Especially since it has been clearly shown by riemming (loc. cit.) that they 

 are constantly undergoing- multiplication. 



*) If, as an objection to the mention of this fact as au indication that the 

 leucocytes are probably coneerned in absorption, it should be iirged that they are 

 also found in considerable numbers in the epithelium of other mucous membranes, 



