100 Journal of Comparative Neurology. 



present in some fields, that this number was sufficient to inner- 

 vate every cell. Sometimes two, three and in some few in- 

 stances four successive cells in a given heart muscle fiber, show 

 a nerve ending, yet when adjacent fibers were observed no end- 

 ings were seen. This might of course be due to imperfect 

 staining. Such heart muscle fibers are often touched by varicose 

 nerve fibers, but the presence of an ending is missed. This 

 question needs therefore further study. 



J. Ending of sympathetic nerves in gland tissues. The 

 problem here involved is one concerning which much has been 

 written, yet it is only since investigators have used the Golgi 

 and methylen-blue methods for its elucidation that anything 

 like a definite answer could be given. As early as 1888 Retz- 

 ius(5o) presented to the Biological Association of Stockholm a 

 short paper, in which the results obtained by staining the nerves 

 of the small salivary glands, found near the papilla foliata of 

 the rabbit, were discussed. In this account Retzius speaks of 

 a plexus of fine varicose fibers surrounding the alveoli of the 

 glands. He was however unable to determine what was the 

 ultimate ending of the fibrils of this plexus or their relation to 

 the gland cells. Ramon y Cajal(5i) shortly after published re- 

 sults obtained by a chrome-silver impregnation of the submax- 

 illary glands of the rat and rabbit. He here describes the non- 

 medullated nerve fibers as entering the gland with the blood- 

 vessels. These fibers form plexuses around the alveoli, from 

 which fibrillae are given off which end on the membrana pro- 

 pria or on the outer surface of the cells. Fusari and Panasci(52) 

 studied the ending of nerves in the small glands of the tongue, 

 also with the Golgi method. They state that the non-medul- 

 lated fibers not only form a plexus around the alveoli but also 

 the gland cells. Marinesco (53), who has published results 

 obtained by staining the glands of the tongue with methylen- 

 blue, states that both meduUated and non-meduUated nerves 

 take part in the formation of the peri-alveolar plexus. From 

 this plexus, which is external to the membrana propria, fibers 

 pass through the membrana and end between the gland cells. 



Korolkow (54), who gives in a preliminary notice results 



