152 DR. E, KLEIN. 



stance, /. e. mucin. The cells lining the alveoli are longer ; this is 

 the more pronounced the more distinctly they stain in logwood, 

 i. e. the more mucin they contain. In some alveoli the lumen 

 is enlarged owing to the presence of a great mass of mucin, and 

 in this instance the diameter of the alveolus as a whole is 

 naturally greater. I see no difference as regards distinctness of 

 the intracellular network, the shape and position of the nucleus, 

 and the distinctness of the membrana propria with its nuclei in 

 the above two states. 



Thus, just as in the submaxillary gland of dog, we see 

 also here that under normal conditions two different states 

 are to be distinguished : {a) one where the gland cells con- 

 tain in the meshes of the network a homogeneous substance 

 corresponding, not to mucin, but to mucigen ; this is the state 

 of rest ; and {h) a state of secretion, when the gland cells increase 

 in size owing to the change of mucigenous substance into 

 mucin, but the intracellular network remains otherwise unaltered. 

 Lavdowsky (1. c.) showed us in addition to these two states a 

 third one, which does not, however, occur under ordinary normal 

 conditions, i. e. {c) a state of exhaustion, when the cells decrease 

 again in size, becoming at the same time more *' granular," and 

 their nucleus more spherical. According to my view of the struc- 

 ture of the gland cells this is not due to an increase of the net- 

 work (protoplasmic part, Lavdowsky), but merely to an exhaustion 

 of the mucigenous, i. e. interstitial, substance. 



Precisely the same two states that we noticed in the normal 

 gland of the dog are found also in the glands of the oesophagus 

 and larynx and soft palate of the same animal. There are, 

 however, certain differences in structure in these different glands 

 which it is necessary to mention here. They are these : while 

 the alveoli of the mucous glands of the tongue possess minute 

 rudiments of what in shape corresponds to nucleated crescents, 

 but what, as I mentioned in conformity with v. Ebner, are 

 merely nucleated parts of the membrana propria (Boll) ; the 

 alveoli of the mucous glands of the oesophagus in the dog possess 

 real protoplasmic '' crescents,'"' independently of the membrana 

 propria and the mucous cells surrounding the lumen. They 

 are granular, nucleated parietal cells in the sense described by 

 Heidenhain of the submaxillary gland. They are not very 

 numerous, not far so numerous as in the submaxillary gland, but 

 sufficiently distinct to be noticeable. Thus I find in one place a 

 '' crescent " that measures 0'038 mm. from one pointed end to 

 the other, and 0*006 mm. in thickness — some crescents are even 

 thicker — and in it five oblong nuclei ; but what is of greater 

 importance is that outside this crescent I trace very clearly the 

 membrana propria, and this possesses a staff-shaped nucleus just 



