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Nachdruck verboten. 
On the Development of the Villi of the Human Intestine. 
By Joun M. Berry. 
(From the Anatomical Laboratory of the Johns Hopkins University, 
Baltimore.) 
With 6 Figures. 
In glancing over the devolopment of the villi of the intestine it 
is found that the information obtained is very meager. It is obvious 
why this should be so, for it is difficult to locate a section through 
a loop of intestine in order to compare it with the same loop in an 
older embryo. Yet it is known that the villi appear at an earlier 
date in the duodenum than lower down, showing that the process must 
be unequal in different portions of the same intestine. 
At the suggestion of Prof. Mati I have undertaken to follow 
the villi of the human intestine from their earliest appearance to a 
stage in which they are fully formed in order to determine their 
history. The sets of sections of human embryos with their recon- 
struction!) in Prof. Marr’s collection made the problem relatively 
easy, as a section of a given loop could in every instance be easily 
located in the model of the entire intestine. 
The summary given by OPPEL?) shows beautifully the comparative 
anatomy of the villi and their evolution. In vertebrates of low order 
the intestine is smooth, no villi being present. Then appear longi- 
tudinal folds, and then all gradations between folds and villi, and 
finally villi. It is interesting to note that in those intestines in which 
folds of the mucous membrane are present, they are more numerous 
and more prominent in the upper part than in the lower part of the 
intestine. As the villi are developed they again appear in the upper 
part of the intestine first, so stages are found with villi in the duo- 
denum, and only folds in the ileum. Furthermore, when villi alone 
are present, they are more numerous in the duodenum than lower down. 
1) Pictures of these models will be found in His’ Archiv, 1897, 
Supplement-Band. 
2) Orrer, Lehrbuch d. vergleich. mikr. Anat., Bd. 2, 1897. 
