THE DEVELOPMENT OF THE MUCOUS MEMBRANE 
OF THE GSOPHAGUS, STOMACH AND SMALL 
INTESTINE IN THE HUMAN EMBRYO 
FRANKLIN P. JOHNSON 
From the Department of Comparative Anatomy, Harvard Medical School 
WITH TWENTY-FOUR FIGURES 
SEVEN PLATES 
The development of the mucous membrane of the digestive 
tract, although studied for many years by competent observers, 
still affords opportunity for further investigation. The present 
work was undertaken for the purpose of studying the development. 
of the structures found in the digestive tract, and to obtain a com- 
parable series of wax reconstructions illustrating the changes 
that take place in the form of the mucosa. Especial stress has 
been laid on the development of vacuoles and diverticula, villi, 
glands, and folds. It was originally intended to include the de- 
velopment of the mucous membrane of the vermiform process 
and the large intestine, but for lack of favorable material, this 
has been omitted in the present paper. This work was suggested 
by Dr. F. T. Lewis, and has been done in connection with his 
chapter on the digestive tract for Keibel’s Text Book of Human 
Embryology. A more complete review of the literature than is 
here given, will be found in Dr. Lewis’ chapter. 
The material used was obtained from human embryos in the 
Harvard Collection. The earlier stages were already prepared in 
the embryological collection. The crownrump lengths and series 
numbers of these are as follows: 
THE AMERICAN JOURNAL OF ANATOMY, VOL. 10, NO. 4. 
