THE STKUCTUBE OF THE GLANDS OF BRUNNEB 



the solutions were rendered neutral or slightly alkaline. The specific ferment upon 

 which this proteolytic action depended, he identified with the pseudopepsin which he 

 had previously extracted from the pyloric mucous membrane. It differed from pepsin 

 in that it was not destroyed, nor its activity removed, by weak solutions of sodium 

 carbonate, and that its action quickly led to the formation of tryptophan. From 

 trypsiii at Was Jjstinfftiished by its activity in acid solutions. 



In view.of faepe experiments of Glassner, Grutzner, and others, it seems certain 

 that'VtIia.'aaJii'of tiie. glands -of Brunner contain a proteolytic enzyme. As yet, how- 

 ever, it is not known whether this is a tissue enzyme concerned in some of the various 

 metabolic processes of the cell itself or a secreted product of the cell designed to assist 

 in the intestine, in the transformation of the proteids of the food. 



Anatomically the main points of interest, as far as the glands of Brunner are con- 

 cerned, have been the form and distribution of the glands, the question as to whether 

 they are mucous or serous glands, the changes they exhibit in different stages of 

 physiological activity, their relationship to the pyloric glands, and their phylogeny. 



The question of the form of the glands has been adequately treated by Schwalbe 

 (1872), whose conclusions that the glands of Brunner are composed of ramifying 

 tubules into which acini open have been confirmed with some additional details, by 

 the studies of Maziarski (1902) and Peiser (1903), who employed the reconstruction 

 method of Born. 



Concerning the mucous or serous nature of the glands, however, there is not the 

 same unanimity of opinion. By many authors, including Schwalbe (1872), Heiden- 

 hain (1872), Bentkowski (1876), and Piersol (1894), they have been compared with 

 the pyloric glands which these authors regarded as similar to the chief cells of the 

 fundus glands. Claude Bernard (1856), Sappey (1876), Renaut (1879), and Berdal 

 (1894) regarded them as mucous glands. Renaut (1879), basing his conclusions on 

 the study of the glands of Brunner of man, regarded them as structures differentiated 

 for the secretion of a peculiar mucus. He compared them with the pure mucous 

 glands of the oesophagus and bronchi, which, according to him, have the same funda- 

 mental structure as the glands of Brunner. 



The same view, in a somewhat modified form, was taken by Kuczynski (1890), 

 who studied in a number of representative mammals the staining reactions of the 

 glandular cells by means of certain synthetic dyes, in particular victoria blue, azoblue, 

 aniline blue, and thionine. These he found to stain the cells of the glands of 

 Brunner of different mammals with different degrees of facility. Some cells, for 

 example those of the pig, were refractory to all attempts to stain them. He concluded 

 that in the latter animal the cells contained no mucin ; that in others, for example the 

 rabbit and horse, where the staining was feeble, the amount of mucin was small ; and 

 again that in the guinea pig and ox, where the cells stained strongly, they contained a 

 large amount of mucin. 



Schaffer (1891) obtained a slight violet coloration of the cells of the glands of 



280 



