360 The Histogenesis of the Adrenal in the Pig 
nishes the answer to this question. It seems to me that he has fully 
demonstrated that the cells which compose what has been termed in 
this paper the mantle are the direct progenitors of the medulla. 
CONCLUSION. 
1. In the pig’s adrenal the anlage of the cortex is laid down much 
earlier than that of the medulla, being first seen at the stage of 8 mm. 
It is probably derived from the coelomic epithelium. 
2. The anlage of the medulla appears first in pigs of 30 to 35 mm., 
at which time it lies spread out like a mantle along the periphery of the 
cortex. The findings indicate that it is derived from the anlages of 
the sympathetic ganglia. 
Since the above was written there has appeared an article by Alfred 
Kohn,” alluding to the existence in various parts of the body of small 
nodular collections of cells characterized especially by the fact that 
they assume a brown color when fixed in chromic solutions. Kohn 
traces the origin of these bodies to the anlages of the sympathetic gan- 
glia, and proposes therefore to call them paraganglia. He believes that 
their extracts possess the property of greatly elevating the blood pres- 
sure. If these interesting views are correct, they furnish further testi- 
mony in favor of the derivation of the adrenal medulla from the sym- 
pathetic; for Henle’s reaction is a property of the medulla, and it is 
well known that extracts of the adrenal elevate the blood pressure. 
I desire to express my indebtedness to Miss M. E. Poindexter for the 
accompanying illustrations. 
14Chromophile Cells and Chromophile Organs, reviewed in Journal of the American 
Medical Association, Chicago, 1902, Vol. XX XIX, p. 706. 
