24 THE STRUCTURE OP THE GLANDS OF BRUNNEB 



visible in many tubules. The cells are of about the same height as the mucous cells, 

 but as a rule narrower and more triangular in outline. 



The two zones visible in the living cell are even more obvious in the stained 

 preparations. The basal clear zone of the living cell is distinguished by its great 

 capacity for staining. In hsematoxylin, carmine, toluidin blue, safranin, and many 

 other nuclear dyes, the basal zone of the cell stains intensely. The substance on which 

 this capacity for staining depends is not evenly distributed in the basal zone, but, as 

 Castellant (1898) has pointed out, gives to the zone an indistinct radially striated 

 appearance (Plate XXI, Fig. 6). 



The inner zone of the cell, unless special precautions have been taken to preserve 

 and stain the granules, appears clear with a fine alveolar structure, the spaces corre- 

 sponding to the granules of the fresh cell, the framework to the cytoplasm separating 

 them. 



By Macallum's microchemical test for organic iron, a very intense positive reaction 

 is obtained in the deeply staining substance of the basal or proximal zone. A similarly 

 intense reaction is obtained in this substance, after extraction of the lecithin by alcohol 

 and ether in a Soxhlet apparatus, by the use of Macallum's microchemical reaction for 

 the detection of organic phosphorus. By the latter method a positive result also is 

 obtained in the granules of the inner distal zone. 



The microchemical reactions indicate that the substance of the basal zone on 

 which the capacity for basic dyes depends is a nucleo-albuniin or nucleoproteicl sub- 

 stance, probably the latter, similar to that found in the basal zones of cells from 

 various serous glands, as, for example, the pancreas, the chief cell of the body of the 

 gastric gland, and the cells of the serous glands of the gustatory area of the tongue, 

 the serous cells of the human submaxillary, etc. For this substance, the writer has 

 employed the term " prozymogen," first used by Macallum (1891), to designate a sub- 

 stance which he found in the pancreatic cell by the use of safranin. He afterward 

 (1895) employed the name to designate the iron-holding organic compound of the 

 basal zone of the pancreatic cell, which he identified with the safraninophilous sub- 

 stance of his earlier studies. In 1895 Mouret described the reciprocal relation 

 between the deeply staining filaments of the pancreatic cell previously described by 

 Eberth and Mflller (1892), Platner (1889), Macallum (1891), and others, and the 

 zymogen granules, and applied independently of Macallum and without being aware 

 of his work, the name "prezymogen" to the substance of the basal zone. In 1896 

 Solger described, without attempting an interpretation of them, the deeply staining 

 filaments in the basal zone of the serous cells of the human submaxillary gland, and 

 Erik Muller (1895) observed similar structures in the submaxillary gland of the 

 guinea pig. In the same year I (1896) published a preliminary account of my 

 researches on the gastric glands of vertebrates, in which it was shown by micro- 

 chemical tests that the so-called basal filaments of serous cells owed their affinity for 

 basic dyes to the fact that they contained a chemical substance "similar to chroinatin 



300 



