SUMMARY OF CURRENT RESEARCHES. 251 



feasibility of this interpretation ; see Herdman's illustration of this in 

 reference to Tunicates ; and (b) that it is not inconsistent with a selec- 

 tionist position to suppose, what Heincke's work on the herring, for 

 instance, seems to us to bear out, that the organism may sometimes at 

 least vary as a corporate unity and not piecemeal, and that selection may 

 operate not directly on the number of rays in a dorsal fin, but on the 

 organism as a whole, as it unconsciously experiments with different modes 

 of constitutional equilibrium.] 



(3) If a sufficiently wide induction be taken both of existing adapta- 

 tions and of their individual development, it seems to the author that 

 we stand in our own light if we refuse the interpretation that the external 

 conditions of life have bad a direct effect in producing adaptive hereditary 

 variations. [It appears to us that some of the objections urged by the 

 author against the selectionist interpretation have been at least partially 

 met many times, e.g. in Weismann's " Germinal Selection." In the light 

 of that essay and others, we cannot agree to Cunningham's statement 

 of the selectionist position in such a sentence as this : " The fitness of a 

 structure or structural mechanism for its function is thus originally 

 accidental."] 



(4) After critically discussing various interpretations of secondary 

 sex characters, Mr. Cunningham points out that on two almost universal 

 peculiarities the theory of sexual selection throws no light whatever : 

 (1) the characters do not begin to appear in the individual until it is 

 nearly adult and sexually mature, and (2) they are inherited only by 

 the sex which possesses them. [The author is forcible and interesting 

 as a critic, but we cannot agree with all his summaries of the views of 

 others, e.g. " Geddes and Thomson regard the male animal as, so to 

 speak, made up of spermatozoa." Is this not too terse to be quite 

 fair ?] 



(5) It seems to the author to have been generally overlooked that the 

 special employment of each special secondary sexual organ subjects it to 

 special, usually mechanical, irritation or stimulation, to which other organs 

 of the body are not subjected. These strains, contacts, and pressures must 

 affect development and mode of growth. And multitudinous facts all 

 agree with the hypothesis that secondary sexual characters are due to 

 the inheritance of acquired characters. 



Mr. Cunningham does not here propose to attempt to prove that 

 acquired characters are inherited ; his object is to show that the hypo- 

 thesis is more effective than any other. [There should be no question of 

 regarding this Lamarckian position with the " more or less courteous 

 contempt " which the author anticipates ; the hypothesis is used as an 

 interpretation throughout the seven chapters of the book, and it seems 

 to work fairly well ; the difficulties which prevent those who side with 

 Weismann from accepting it do not weigh with Mr. Cunningham ; and 

 so the question will remain — one opinion against another — until con- 

 clusive experimental evidence is forthcoming.] 



(6) "It is obvious," the author says, "that if the removal of the 

 testes can affect the development of tissues in the head, the development 

 of the latter may affect the properties of the testes," and thus future 

 offspring. [The unity of the organism being what it is, it would be rash 

 to deny that any one part may not affect any other, but must we not 

 adhere to what is demonstrable ? We know that the testes affect the body, 



