206 On Trophic Nerves. [April, 



cord of such an amount of stimulus as was competent to throw the 

 tissues of the lower parts of the body into active chemical change. 

 That this explanation is a vera causa the following facts will show. 

 Dr. Semper, in his magnificent work on the Philippine Archipelago,* 

 has given us an account of certain Echinodermata, of the class 

 Holothurioidea, the source of the article of commerce known as 

 " trepang," from which we learn that several of these curious animals 

 have the power of dissolving then integument into a kind of amor- 

 phous slime, upon irritation even of so gentle a kind as simple 

 removal from the sea water. In the case of one species, Stichopus 

 naso, it has been found necessary to kill them by heating the water 

 without removing them from it, as otherwise their dense integument 

 runs into dissolution, and the animal is spoilt for the Chinese market, 

 in which, when well preserved, it commands a specially high price. 

 If, now, fragments of the integument of one of these creatures be 

 placed under the microscope, and whilst there, be irritated with the 

 point of a needle, the process of self-dissolution is observed to be 

 expedited in direct correspondence with the amount of stimulus 

 applied. In this diffluent slimy mass beautiful reticular and nucleate 

 nerve-plexuses are to be seen, surviving, which is not always the lot 

 of destructives, the destruction they have brought about. Kothing 

 can speak more clearly to the " catalytic" power of nervous organs, 

 unless it be the rationale given by Mr. Paget, as reported in the 

 British Medical Journal for January 22, 1870, of the formation 

 of sloughs and bed-sores. There Mr. Paget is reported to have 

 observed that " simple loss of nerve-power is followed only by toasting 

 of the paralyzed parts ; but if in addition to loss there is disturbance 

 of nerve-force, we then find disturbances of nutrition quickly follow- 

 ing the injury, such as extensive bed-sores and sloughing of integu- 

 ment on the feet." To this we should add that if the nerve-system 

 does not play the part of King Stork, other irritants may ; and that 

 animal structures deprived of the eminently animal assistance which 

 a connection with a central nervous system secures to them succumb 

 to shocks to which, when thus reduced almost to the level of vege- 

 table tissues, they ought not in fairness to have been exposed. The 

 discordant results of observations as to the consequences of paralysis 

 of many, and especially of the trifacial nerves, can be harmonized if 

 these two considerations are kept before the mind. 



For the literature of this subject and much else that is valuable 

 relating to it, see Handfield Jones, ' St. George's Hospital Reports* 

 iii., 1868, p. 89; Funke, 'Lehrbuch der Physiologic,' Bd. ii., 62 

 to 775; 1866: Herman, ' Grundriss der Physiologie,' pp. 79, ^!93, 

 298; 1867: Br. Anstie, in 'The Practitioner; March, 1870, p. 166. 



* ' Eeisen im Archipel der Philippine!!,' iii., 72 ; iv., 158, 171 ; v., 200. 1868. 



