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



Occasionally, indeed, there appear to be more, but in such 

 cases there is always a doubt whether the line of division 

 between two adjoining cells is perceptible. 



According to Heidenhain, there are two kinds of salivary 

 cells, of which one contains mucus, but no albumen ; the other 

 albumen, but no mucus. The former he denominates " mucous- 

 cells," the latter "albuminous-cells." Both are glassy, trans- 

 parent, and delicately striated ; the latter are, in addition, finely 

 granular. Where mucous cells predominate, as in the sub- 

 maxillary gland of the dog, cat, ox, and sheep, they may perhaps 

 represent the young condition of the albuminous cells. In 

 the rabbit, at least in the submaxillary gland,* no mucous cells 

 are, according to this observer, to be found. 



Besides the points already described, there still remains to 

 be noticed a structure, first mentioned by Gianuzzi, and to 

 which he has applied the term semi-lunar body.f 



When sections are made of hardened salivary glands, there 

 appears here and there a concavo-convex lenticular lamina, 

 usually of very small thickness, which adheres intimately to 

 the alveolus surrounding the salivary cells that lie in its 

 cavity, and presents, on section, a semi-lunar form But in- 

 asmuch as, on investigation of fresh glands, I was never able 

 to see the semi-lunar body, and found that even in rab- 

 bits it eluded my observation, I was inclined, since this 

 structure is only demonstrable in those animals which have 

 mucous cells, to regard the semi-lunar body as an artificial pro- 

 duct, and as originating in the post-mortem formation of a 

 mucous vesicle, compressing the cell protoplasm towards the 

 wall. And it is remarkable that, according to the recent in- 

 vestigations of Heidenhain, the submaxillary gland of the dog, 

 when the mucus is withdrawn from it, no longer presents the 

 demi-lune, but resembles the same gland in the rabbit.^ The 

 elimination of the mucus is effected by exciting the gland to 



* See Heidenhain, loc. cit., p. 6. 



t S. Gianuzzi, " On the effects of acceleration of the blood currents 

 on the secretion of Saliva ; " Ber. d. K. Sachs Ges. d. wiss. Math. Phys. 

 Classe, Sttzung vom Nov. 27, 1865, 



: Heidenhain, loc. ctt., Taf. ii., fig. *. 



