HuBER, Sensojy Netve-fibcrs in Visceral Nerves. 141 



endings described by Ploschko differ widely from the primary, 

 secondary and tertiary plexuses found in involuntary muscle tis- 

 sue, and could not be mistaken for them, I feel warranted in 

 saying that so far as my observations go, such sensory endings 

 in involuntary muscle tissue have not a wide distribution. I 

 have never met with them in numerous methylen blue prepara- 

 tions of the intestine, bladder or gland ducts. I have dwelt 

 somewhat fully on this observation of Ploschko, since I believe, 

 as will appear later, that sensory nerves to the viscera do 

 not end in the muscular coat. Berkley (14) in his account 

 of the intrinsic pulmonary nerves of mammalia, describes 

 nerve fibers which come from the larger nerves accompanying 

 the bronchi — presumably medullated nerves — and pass into the 

 folds of the bronchial mucous membrane, and end in arboriza- 

 tions ; also nerves which end in arborizations between the epi- 

 thelial cells of the smallest bronchi. These, it seems to me, 

 must be looked upon as sensory nerve fibers of the bronchi. 

 More complicated sensory endings found in the lung 

 of the frog have been described by Smirnow (15); he 

 speaks of them as " Nervenendknauel." They are formed by 

 the repeated division of the neuraxes of medullated fibers, the 

 terminal branches interlacing and anastomosing. Cuccati (16) 

 has described similar endings in the lung of the frog. Smir- 

 now (17) has described sensory nerve endings in the endocard- 

 ium and pericardium, and Dogiel (18) has corroborated and 

 greatly extended these observations. Ehrlich (19) in his first 

 paper on the methylen blue method, mentions a peculiar term- 

 inal apparatus found in the bladder of the frog, to which the 

 name " Endbaumchen " was given. The terminal arboriza- 

 tions found in the frog's bladder were further described by Cuc- 

 cati (20) and on a former occasion the writer (6) has figured 

 them and otherwise called attention to them. While this ac- 

 count was being written there came into my hands an article by 

 Griinstein (21) working in Arnstein's laboratory, in which he 

 gives the results of observations, made with the methylen blue 

 method, on the innervation of the bladder in the frog, mouse, 

 rat, cat and dog. In this article Griinstein calls attention to 



