518 Intestinal Diverticula in Embryos of the Pig, Rabbit, and Man 
rence. Retterer” has figured such cases, and one of Klein’s figures sug- 
gests that an area of intestinal glands has become depressed to form a 
pocket. Such formations have little resemblance to the intestinal diver- 
ticula. Several of Klein’s figures, however, show the same sort of sub- 
mucous glands as Stohr found in the guinea-pig, and these strikingly 
resemble the diverticula. In the pig after birth, Klein found them only 
in the large intestine. 
We are indebted to Professor Theobald Smith for a demonstration of 
these structures in a young pig. Their relation to certain infections, as 
described by Klein, is important, for they become centers of ulceration. 
Often their lumen contains a concretion which is easily macroscopic. 
In discussing Retterer’s paper, to which reference has been made, His 
pointed out that lymphoid tissue develops in relation with very various 
epithelial folds and pockets, such as the vermiform process, the tonsillar 
pits, pharyngeal recess, and intestinal glands. If this “ general prin- 
ciple” is true, then the relation of the flask-shaped pockets of the intes- 
tine to lymphoid tissue is secondary, and the function of the pockets 
themselves must still be sought. 
Stohr (1. c., p. 24) states that the structures in question are “ diver- 
ticula lke the other intestinal glands, and are distinguished from them 
only by their breadth and the possession of lateral sprouts. The name 
glands is indeed unfortunate since they produce no specific secretion.” 
Like the intestinal glands, they may produce mucus, but this is not, in 
Stohr’s opinion, a sufficient reason to call them glands rather than pits. 
Klein speaks of their distension with mucus. 
Solid knob-like diverticula similar to those of mammalian embryos have 
been found by Bizzozero” along the intestine of the tailed amphibia. 
They contain four elements—young epithelial cells, young mucous cells, 
cells in mitosis, and coarsely granular leucocytes. Bizzozero places em- 
phasis upon the mitoses, and regards the knobs as centers for the pro- 
duction of cells to replace those lost from the surface. ‘The knobs are 
less definite in the tail-less amphibia, in the lower vertebrates, and in 
reptiles. In mammals the mitotic centers are near the bases of the 
intestinal glands, and Bizzozero considers that these glands are therefore 
comparable with the solid diverticula of the amphibia. In various insects 
* Retterer. Sur l’origine des follicules clos du tube digestif. Verh. d. anat. 
Gesellsch., 9th Versammlung, 1895, p. 31-39. 
*1 Bizzozero, G. Ueber die Schlauchformigen Dritisen des Magendarmkanals 
und die Beziehung ihres Epithels zu dem Oberflachenepithel der Schleimhaut. 
III. Arch. f. mikr. Anat., 1893, Vol. 42, p. 82-152. 
