148 DR. E. KLEIN. 



lobules containing mucous gland structure, we ascertain with un- 

 mistakable clearness that the alveoli lined only with mucous cells 

 are directly continuous with alveoli lined for a greater or smaller 

 section with granular cells, the rest being mucous cells, and, 

 fm'ther, with alveoli, which are altogether lined only with 

 granular cells. Those alveoli that are only partly lined with 

 granular cells resemble in many instances the alveoli of dog's 

 submaxillary gland, viz. the central cells being mucous cells, 

 whereas the granular cells form the crescents. That alveoli 

 of this kind are directly continuous with such that are lined ex- 

 clusively with granular cells, of this I have convinced myself 

 quite positively.! It is hardly necessary to add that the last- 

 named alveoli are smaller than the others. 



I have been able to confirm this observation made on Case a, 

 also in Case /3. In both instances I find in those alveoli that 

 are lined with mixed epithelium the mucous cells possess a nucleus 

 less compressed and not so close to the membrana propria as in 

 the alveoli that are lined only with mucous cells. 



That the intermediary forms, previously stated, are not due 

 merely to different stages of development of mucous gland-struc- 

 ture, as in the submaxillary gland of half-grown dog, but 

 probably to different states of function, is shown in Cases /3 and 

 -y, which, aUhongh belonging to older individuals, shoiv less of the 

 mucous gland-structure than in Case a. 



We are, then, led to the conclusion that there exists an 

 intimate relation between the gland-structure lined only with 

 "granular'^ cells and such with only mucous-cells. Boll, in the 

 above-named work, stated that in the submaxillary gland of 

 guinea-pig the alveoli are either lined by mucous cells or by pro- 

 toplasmic 'Agranular"' cells, and he concluded that whole lobules 

 are capable of being transformed into mucous-secreting struc- 

 tures. The submaxillary gland of dog is, according to the same 

 author, the one extreme ; that of the guinea-pig, in which all 

 alveoli are lined by '^ granular ^^ cells, is the other extreme; that 

 of man is intermediary between the two. 



Lavdowsky denies this, and maintains that the two structures, 

 — viz. alveoli lined with mucous cells and such Hned with 

 "granular" cells — are entirely independent of each other, and 

 are only cO' existing side by side, as is the case in the submaxil- 

 lary gland of man, or, as is still more evident, in the root of 

 tongue, where we find side by side both varieties of gland- 

 structure, viz. serous glands and mucous glands (v. Ebner). 



^ The examination on this point is greatly facilitated by the distinctness 

 with which we are enabled to trace what belongs to one and the same 

 lobule, owing to the fact — as above mentioned — of the presence of consi- 

 derable masses of connective tissue between the lobules. 



