ROBERT RUSSELL BENSLEY 43 



chloric acid and in artificial gastric juice containing 0.2 per cent, of hydrochloric acid. 



The structure of the cells also supports the conclusion that they are mucous cells. 



The cells of the glands of Brunner differ in structure according to the physio- 

 logical phase in which they happen to be when examined. Three well-defined stages 

 may be discerned: In the condition of maximum loading the cells are large and 

 transparent. They contain a flattened or crescentic nucleus, located in the base of the 

 cell, surrounded by a small quantity of finely reticular cytoplasm. The body of the 

 cell is clear and shows a coarse network of cytoplasmic trabeculae in the meshes of 

 which the secretion is lodged. 



In the intermediate condition, the nucleus is more oval in outline, the basal 

 cytoplasm is greater in amount and the body of the cell exhibits two distinct secretory 

 zones. In the proximal zone the granules of secretion are separated from one another 

 by cytoplasmic trabeculse coarser than those of the distal zone. (See Fig. 2.) 



In the discharged condition the nucleus is spherical or oval and nearer the center 

 of the cell. The basal cytoplasm is increased in amount. The secretion may be con- 

 fined to a mass on the free border of the cell, or there may be two masses, a dense one 

 on the free border (referred to in the specific descriptions as the distal mass) and a less 

 dense one (the proximal mass) composed of smaller granules, in the interior of the cell. . 



The two latter conditions may be reached either as stages in the discharge of the 

 cell, or in inverse order, as stages in its recovery during a period of rest after discharge 

 of its secretion. 



In the writer's opinion, the obvious subdivision of the secretion into two masses is 

 due to the fact that the new secretion is formed in the neighborhood of the nucleus in 

 the interior of the cell. This may be due, as suggested above, to the action of enzymes 

 produced by the nucleus, or it may be due to the effect of the presence (of which the 

 writer has not yet been able to obtain evidence) in these cells of structures similar to 

 the so-called trophospongium observed by Holmgren (1902) in various epithelial cells. 



A similar secretory mechanism has been shown to exist in the various mucous 

 salivary glands by the studies of Maximow (1901) and Kolossow (1903). Both of 

 these writers have noticed the obvious division of the secretory portion of mucous cells 

 into two zones, and Maximow has also observed the new formation of secretion granules 

 in the neighborhood of the nucleus. I have (1898, 1902) demonstrated similar condi- 

 tions in the cells of the palatine glands, pyloric glands, cardiac glands, and in the 

 mucous neck chief cells of the fundus glands of mammals. Krause (1895) has also 

 described the formation of new secretion near the nucleus in the mucous cells of the 

 retrolingual glands of Erinaceus. 



The conclusion that the glands of Brunner are mucous glands is concurred in by 

 a number of writers mentioned in the introductory paragraphs. Castellant (1898), 

 Kuczynski (1890), and Schaffer (1891) came to a similar conclusion, with some reserva- 

 tions. The two former, using various synthetic stains and ordinary solutions of 

 hsematoxylin, have observed that the secretion of the glands of Brunner of different 



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