4G6 DR. ST. GEORGE M1VART ON THE DEVELOPMENT [June 17, 



and other animals, and also of our own highest and most complex 

 instinctive actions. 



I will now revert to the consideration of certain actions, in our- 

 selves and other animals, which actions are not generally reckoned 

 as " instinctive." The characters presented by the actions of the 

 lowest animals may serve as an introduction to them. 



Iu the first place let us glance at those actions which are termed 

 "reflex." Herein it is commonly supposed that the living me- 

 chanism occasions a prompt responsive muscular action upon the 

 occurrence of some unfelt nerve-stimulation. The best-known 

 examples are the appropriate actions, in response to stimuli, per- 

 formed by a decapitated Frog, and those which the lower limbs of a 

 Man may execute when the nerves of his feet are stimulated after his 

 spinal cord has been so injured that he has lost all power of sensation 

 in his inferior extremities. It has been objected by the late Mr. 

 G. H. Lewes and others that we cannot be sure but that the spinal 

 cord itself "feels." But there is often an ambiguity in the use of 

 the term "to feel." By it we ordinarily mean a "modification of 

 consciousness," but experiences such as those before adverted to, and 

 which I have provisionally called " unfelt sensations," show clearly 

 that effects may be produced by surrounding agents on our sense- 

 organs without the intervention of consciousness, similar to those 

 produced on them when they do arouse consciousness. Without 

 then entering into any discussion as to whether " sentiency " may or 

 may not be attributed to the spinal cord, it seems evident that some 

 definite term is required to denote those modifications of our being 

 which have here been provisionally termed " unfelt sensations." 



It is obviously very difficult, probably impossible, to draw any 

 hard and fast line between reflex action, unfelt sentiency, and such 

 unconscious, instinctive impulses as have been above referred to in 

 speaking of Instinct in man. 



There is also another class of organic vital actions which seem to 

 have a certain affinity both to reflex action (from their perfect 

 unconsciousness) and to Instinct, from their being directed towards 

 a useful but unforeseen end. The class of actions here referred to 

 are those which relate to the repair of injuries and the reproduction 

 of lost parts. 



In a process of healing after a wound, a true secretion is poured 

 forth of intercellular substance in which cells are abundantly formed, 

 and, by a process of transformation, vessels, tendons, nerves, bone, 

 and membrane all arise, as they originally first arose in the embryo, 

 from undifferentiated cellular substance. 



In a case of broken bone, the two broken ends soften and a sub- 

 stance is secreted which becomes at first gelatinous, often afterwards 

 cartilaginous, and finally, osseous. 



But not only distinct tissues, but very complex teleological 



structures, such as admirably formed joints, may be reproduced. 



Thus we read 1 that "a very interesting example is recorded by Mr. 



Syme, in which he had the opportunity of dissecting the new joint, 



1 See Mr. Timothy Holmes's ' System of Surgery,' 3rd edition, vol. iii. p. 74l>. 



