462 DR. ST. GEORGK MIVART ON THE DEVELOPxMENT [Juiie 17, 



12, On the Development of tlie Individual and of the 

 Species as Forms of Instinctive Action. By St. George 

 MivART, V.P.Z.S., Ph.D., M.D., F.R.S. 



[Receired June 17, 1884.] 



The object of this paper is to endeavour to show that the clearest 

 comprehension of Ontogeny and Phylogeny is probably to be 

 obtained by regarding them as special forms of Instinctive Action. 

 In order to make this conception intelligible, it is necessary to begin 

 by considering " Instinct" itself. 



Instinct has been very generally considered to be an altogether 

 pecuhar phenomenon, very distinct from all the other powers ])os- 

 sessed bv animals. Attempts have, however, been made to explain 

 it by " reflex action " on the one hand, and by " conscious deliberate 

 intelligence" on the other. It has by some persons been regarded as 

 "compound reflex action" in which sensation intervenes. It has 

 by other persons been considei-ed as made up of the relics and 

 remains of intelligent acts, which acts were once performed with deli- 

 berate purpose and intention, but which have become so extremely 

 habitual as, at length, to be performed without the intervention of 

 any consciously intelligent purpose on the part of the creatures 

 which perform them. 



To appreciate fully the bearing of Instinct on Ontogeny and 

 Phylogeny, we should also see what are its relations to the other vital 

 processes — such as reflex action and the repair and reproduction 

 of lost parts after injury. Before entering upon this question, 

 however (the question of the relations existing between Instinct and 

 the various other vital processes), it will be well to start with a 

 declaration as to what is meant by the term Instinct in the present 

 paper. 



The general notion of " Instinct " is that of a special, internal 

 " impulse urging animals to the performance of certain actions 

 which are useful to them or to their kind, but the use of which 

 they do not themselves perceive, and their performance of which is 

 a necessary consequence of their being placed in certain circum- 

 stances " K Such actions can, however, only be considered as 

 being generally useful — useful in the great majority of instances, 

 as Instinct every now and then impels animals to perform an act 

 prejudicial to the individual performing it in some particular case. 



That we may securely proceed from the more known to the less 

 known, it will be best to begin with a consideration of Instinct'' as it 

 exists in Man ; since we can know no creatures so well as we can, 

 bv the help of language and reflection, know ourselves and our own 

 species. 



* Todd's Cyclopa?dia, vol. iii. p. 3. 



' " Instinct " as such (like " life," " mind," &c.) is, of course, a pure abstrac- 

 tion, and exists thus only in our minds, though it has a real existence enough, in 

 certain concrete actions which animals perfciriu. 



