456 THE SALIVARY GLANDS, BY E. F. W. PFLUGER. 



tion developed at the periphery of the alveoli In rabbits, the 

 secretion of saliva in the submaxillary gland is effected, ac- 

 cording to Heidenhain, exceptionally without demonstrable 

 disintegration and neoplastic cell formation. 



The important and novel principle in respect to the action 

 of the nerves, established by the observer just mentioned, can- 

 not be here passed over in silence. I have placed an investi- 

 gation into the accuracy of his statements into the hands of my 

 pupil, Herr Anton Ewald, of Berlin, who has been for some 

 time engaged under my superintendence with the structural 

 changes induced by excitation of these glands, and has pur- 

 sued precisely the same method as that adopted by Heidenhain. 

 After one submaxillary gland had been excited for a consider- 

 able period (as long as for seven hours) whilst the other had 

 been kept at perfect rest, both were removed from the living 

 animal, and from these thin sections were made with a razor, 

 which were immediately thrown into a large quantity of abso- 

 lute alcohol. By this means we avoided, as far as possible, in 

 the unexcited gland, which is charged with mucus-forming sub- 

 stance (" mucigen "), the production of any material structural 

 alteration through the post-mortem formation of mucous vesi- 

 cles in the alveoli, consequent upon displacement of cells and pro- 

 toplasm. This precautionary measure was not unnecessary; 

 for in the gland, which has been for a long time actively dis- 

 charging its function, no more " mucigen " is contained, and, 

 therefore, in this case, no alteration of structure can occur from 

 the formation after death of mucous vesicles. 



When both glands had been hardened for an equal time in 

 alcohol, very fine sections were prepared, macerated for the 

 same period in the solution of carmine in glycerine, employed 

 by Heidenhain, and finally, after the most careful {washing, 

 examined in glycerine. It is obviously a matter of great im- 

 portance that the sections should be made as fine as possible, 

 and all those that are thicker than the diameter of a salivary 

 cell should be rejected. If the cell mosaic lining the interior of 

 the alveoli of the quiescent gland be examined, we find for the 

 most part a single layer of sharply defined transparent poly- 

 gonal cells flattened by mutual pressure, which, however, are 

 not perfectly hyaline, but exhibit a delicate striation, as though 



