142 Journal of Comparative Neurology. 



relatively large medullated nerves which pass through the gang- 

 lia found in the wall of the bladder (well shown in Fig. 6, PI. 

 I, of his article) which end in large terminal arborizations. I 

 hope to make further reference to his observations on the termina- 

 tion of the ultimate branches of such arborization somewhat later. 

 On account of the many observations here referred to, I should 

 not have felt a need at the present time of calling special atten- 

 tion to the subject under discussion, had I not found in Barker's 

 (22) recent and most admirable volume on the nervous system, 

 which must be looked upon as summarizing in a concise and 

 impartial way our knowlege of the nervous system, the follow- 

 ing statement : 



"Whether or not the complex feltwork of fibers found 

 throughout the heart have to do with the mediation of centripetal 

 impulses or whether they are concerned wholly with the carrying 

 of motor impulses to the heart muscle fibers has not been de- 

 termined. Similar doubt exists concerning the nature of nerve 

 endings in smooth muscle ; enormous numbers of fine fibrils 

 have been found in smooth muscle membranes, and their exact 

 relation to the fibers has, in some cases, been carefully studied ; 

 but how many of them are motor and how many of them are 

 sensory, remains for further investigation to determine. Cer- 

 tain it is that the walls of tubes which have smooth muscle coats 

 are well supplied with sensory nerves. To make this clear I 

 have only to mention the intestine, the bile duct, the bladder, 

 the uterus and blood vessels." " Whether the pain in these is 

 the result of stimulation of sensory nerve fibers beginning in 

 the muscle itself or in the connective tissue is not known." 



The writer has for some years made use of the methylen 

 blue method for gaining a clearer understanding of the innerva- 

 tion of the various tissues and organs of examples of the differ- 

 ent classes of vertebrates, and although the sensory visceral 

 nerves have not been the subject of a special research, he has 

 had frequent opportunity to study preparations which throw 

 light on the subject undei discussion and it is my purpose to 

 give, in the remaining portion of this paper, some general conclu- 

 sions reached, rather than give in detail many fragmentary ob- 



