THE STRUCTURE OF THE MAMMALIAN CSOPHAGUS. 
I BY 
EMIL GOETSCH. 
From the Hull Laboratory of Anatomy, University of Chicago. 
WiTH 17 FIGURES. 
One of the most interesting features in the structure of the Mam- 
malian Cfsophagus is the extreme variability in the degree of devel- 
opment of the csophageal glands in different species. For example, 
according to Ranvier (84) and others, the esophagus of the rabbit, 
guinea-pig and rat is wholly devoid of glands, while in the dog, a 
thick layer of mucous glands nearly filling the submucous coat is 
found throughout the whole extent of the organ. Nor is this dis- 
parity confined to species belonging to different orders, for the 
cat and dog among carnivora and the sheep and pig among ungulates 
present equally striking differences in this respect. 
The reasons which have been advanced for this disparity are based 
on the assumption that the function of the csophageal glands is to 
furnish a secretion which will serve to lubricate the surface of the 
cesophageal mucous membrane and so facilitate the passage of the 
bolus of food in deglutition. Assuming that the secretion of the 
cesophageal glands possesses this purely mechanical function, the 
logical conclusion is that their development will be influenced by 
several factors which determine the consistence of the food-bolus 
which is to be swallowed, such for example as the character and bulk 
of the food itself, the efficiency of the masticatory mechanism, and 
the relative development of the salivary glands furnishing a secre- 
tion by means of which the food is diluted and rendered of softer 
consistence. Accordingly, various attempts have been made to 
establish a correlation between the degree of development of the 
salivary glands and the efficiency of the masticatory mechanism on 
THH AMDERICAN JOURNAL Or ANATOMY.—VOL. 10, No. 1, JAN., 1910. 
