46 Transactions of the 



not to any direct influence propagated by the nerve to the proto- 

 plasm (bioplasm) by reason of continuity of material. 



The drawing in Plate VI. will serve to illustrate the only con- 

 clusion I can accept at this time with reference to this interesting 

 question. Although I publish only this one drawing, the fact has 

 been observed in many instances, and in many different animals. 

 In no case have I been able to satisfy myself that the nerve 

 ends in the manner M. Pouchet describes, and which accords with 

 the conclusions arrived at by some other observers who have studied 

 somewhat similar structures. I believe, however, that upon this 

 matter my own conclusions as regards the non-continuity of the 

 nerve fibres with the cell are in accordance with the more recent 

 observations of Dr. Klein, though this observer describes a plexus 

 of excessively fine nerve fibres upon or over the protoplasm (bio- 

 plasm) of the corneal connective-tissue corpuscles, as demonstrated 

 by the use of chloride of gold, but which is not seen in my speci- 

 mens prepared according to a difierent method of investigation. 



As far as I have yet been able to extend my inquiries I feel 

 confidence concerning the results arrived at. I am quite certain of 

 what I have described, and equally sure I can demonstrate the facts 

 to others. That there may be still finer nerve fibres is of course 

 quite possible, but for the present I prefer to discuss the bearing of 

 what I have myself been able to demonstrate conclusively, rather 

 than to reason upon the observations of others, more especially as 

 the facts I have adduced have in nearly all cases been confirmed by 

 a number of observations upon diff"erent tissues in different animals, 

 and at varying periods of life. 



The drawing illustrates the appearances observed in the neigh- 

 bourhood of one of the prolongations of a solitary pigment corpuscle 

 in a beautiful specimen of the dehcate fibrous membrane from the 

 abdominal cavity of the Hyla, or green tree frog. The portion of 

 tissue under observation displayed the various points represented 

 with great distinctness, and though it was magnified by the -i^^ of 

 an inch object-glass, magnifying nearly 3000 linear, made by 

 Messrs. Powell and Lealand, so thin w^as the specimen that httle 

 difficulty was experienced in getting clear views of every part. 



The branch of the pigment cell (c) is seen in the central part of the 

 drawing, and the granules of pigment suspended in the transparent 

 fluid material flowing in the tubular cavity are represented. The 

 nerve fibre (a) prolonged from the elongated nucleus (bioplasm of the 

 nerve) is seen to divide into two branches, one of which crosses the 

 pigmentaiy process, while the other pursues a course for a short 

 distance parallel to it. If, as often happens, a fine nerve fibre 

 runs very close to one of the processes for a short distance, and is 

 then lost to view in consequence of passing behind the body of the 

 ceU, and is perhaps hidden by a thicker portion of fibrous tissue, 



