PHYSIOLOGY OP PEPSIN-FORMING GLANDS. 
G83 
BUFO VARIABILIS. 
Histology of the (Esophageal and Gastric Glands. 
Much less attention has been given to the structure and arrangement of the pepsin¬ 
forming glands in the Toad than to their structure and arrangement in the Frog. 
Swiecicki* apparently considers that in both these points the two are alike. He 
treats the question, however, very briefly, simply mentioning at the end of his paper 
on the oesophageal and gastric glands in the Frog, that as regards the estimation of 
pepsin, he obtained in the Toad results similar to those obtained in the Frog. 
PartschI denies that any glands resembling the oesophageal glands of the Frog 
are to be found in the oesophagus of the Toad. He found in the latter no pepsin¬ 
forming, but only mucous glands. 
My own observations lead me to take up an intermediate position between these 
observers. Of the oesophageal glands of the Toad a very considerable number are, it 
is true, mucous glands, but pepsin-forming glands also occur ; these, however, differ 
in many points from the pepsin-forming glands of the oesophagus of the Frog. 
In the Toad it is less easy than in the Frog to tell exactly where the oesophagus 
ends and the stomach begins, for there is no constant constriction between the two 
regions, nor is there any change in the character of the glands sufficiently abrupt to 
enable a distinction of oesophageal and gastric regions to be drawn, and, as was 
observed by Partsch, the cylindrical cells of the surface of the oesophageal mucous 
membrane are devoid of cilia. 
There is, however, one means of distinguishing the oesophagus from the stomach, 
viz., by observing the closeness of attachment of the muscular and mucous coats. In 
the stomach the two coats can be much more easily separated than in the oesophagus. 
It is by the use of this method that I have judged where the oesophagus ends and the 
stomach begins. It seems to me that if this method is rejected there is no alternative 
but to consider all the glands, mucous glands included, as occurring in the stomach, for 
there is no abrupt change in structure in passing from mucous to pepsin-forming glands. 
The question is, however, not an important one, the important question being, Is 
there any differentiation in the structure and function of the glands, such, for instance, 
as occurs in the Frog \ 
In examining sections of the mucous membrane which has been treated with osrnic 
acid, proceeding from the beginning of the oesophagus onwards, we first find short 
simple mucous glands as described by Partsch, then in the mucous glands are found 
one or two cells containing a few large granules; further on these cells become more 
frequent and contain more granules, until we come to the regular oxyntic glands ; in 
these the body is usually long, and frequently coils or branches at its end ; the mucous 
cells are confined to tire necks of the glands. The granules contained by any one cell 
* Op. cit. f Op. cit. 
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