J. F. GASKELL 



79 



The structure of these adrenalin-containing cells justifies the con- 

 clusion that they are nerve cells, and the question arises whether 

 they innervate some special musculature which is susceptible to the 

 action of adrenahn. That is to say, are they the representatives of the 

 sympathetic cells of the vertebrate as well as the representatives of 

 the adrenalin-secreting cells of the suprarenal medulla? If this is so, 

 in this primitive stage of development, such a nerve cell not only 



r m tn' n ^ n 'tn< u iin^ <tn'.uiunnM»u until 



Fig. 2. The action of an extract of leech gangUa upon the virgin uterus of the 

 cat. The isolated uterus was suspended in a bath of 50 cc. of Ringer's solution, 

 to which histamine had been added to produce a strength of 1 in 3 millions; a 

 good tone and rhythm were thus obtained. At A the extract of 400 leech gangUa 

 ground up with sand in 2 cc. of Ringer's solution was added to the bath. A dimi- 

 nution in both tone and rhythm was produced. Time markings at intervals of 

 10 seconds. 



regulates its peripheral musculature by direct nervous action but also 

 provides the internal secretion which is necessary for the proper 

 action of its nervous impulses. Later developments have caused a 

 differentiation from this primitive state, so that two separate types 

 of cell have arisen, one of which has become the adrenalin-secreting 

 cell, the other the sympathetic nerve cell. Kohn^ considers that in 

 the early mammalian embryo the two types of cell arise from a com- 

 mon mother cell, and may develop into either chromaffin cells or 



