686 PSYCHOLOGY. 



The inheritance of tricks of manner and trifling peculi- 

 arities, such as handwriting, certain odd gestures when 

 pleased, peculiar movements during sleep, etc., have also 

 been quoted in favor of the theory of transmission of ac- 

 quired habits. Strangely enough ; for of all things in the 

 world these tricks seem most like idiosyncratic variations. 

 They are usually defects or oddities which the education 

 of the individual, the pressure of what is really acquired 

 by him, would counteract, but which are too native to be 

 repressed, and breaks through all artificial barriers, in his 

 children as well as in himself. 



I leave my text practically just as it was written in 1885. 

 I proceeded at that time to draw a tentative conclusion to 

 the effect that the origin of most of our instincts must cer- 

 tainly be deemed fruits of the back-door method of genesis, 

 and not of ancestral experience in the proper meaning of 

 the term. Whether acquired ancestral habits played any 

 part at all in their production was still an open question in 

 which it would be as rash to affirm as to deny. Already 

 before that time, however, Professor Weismann of Freiburg 

 had begun a very serious attack upon the Lamarckian 

 theory,* and his polemic has at last excited such a widespread 

 interest among naturalists that the whilom almost unhes- 

 itatingly accepted theory seems almost on the point of 

 being abandoned. 



I will therefore add some of Weismann's criticisms of the 

 supposed evidence to my own. In the first place, he has a 

 captivating theory of descent of his own,t which makes him 

 think it a priori impossible that any peculiarity acquired 

 during lifetime by the parent should be transmitted to the 

 germ. Into the nature of that theory this is not the place 

 to go. Suffice to say that it has made him a keener critic 

 of Lamarck's and Spencer's theory than he otherwise might 

 have been. The only way in which the germinal products 

 can be influenced whilst in the body of the parent is, accord- 



* Ueber die Vererbung (Jena, 1883). Prof. Weismann's Essays on 

 Heredity have recently (1889) been published in English in a collected 

 form. 



f Best expressed in the Essay on the Continuitat des Keimplasmas (1885). 



