154 EVIDENCE OPPOSED TO 



OPPOSING EVIDENCE 



We have now to review certain cases which seem 

 to support conclusions contrary to those which we 

 have maintained in the preceding pages, and to 

 consider the evidence which has been published in 

 support of other theories. It must be admitted that 

 the occurrence of male secondary characters on one 

 side of the body, and female on the other, is incon- 

 sistent with the view that the development of such 

 characters is due to the stimulus of a hormone, since 

 the idea of a hormone means something which 

 diffuses by way of the blood-vessels, lymph- vessels, 

 and interstices of the tissues, throughout the body, 

 and the hormone theory of secondary sexual char- 

 acters assumes that these characters are potentially 

 present by heredity in both sexes. The occurrence 

 of male somatic characters on one side or in one part 

 of the body and female on the other, usually 

 associated with the corresponding gonads, has been 

 termed gynandromorphism, and has long been 

 known in insects. Cases of this condition have been 

 observed, though much more rarely, in Vertebrates. 

 I am not aware of any authentic instance in Mammals, 

 and the supposition that in stags reduction or 

 abnormality of one antler may be the result of 

 removal or injury to the testis of one side, or the 

 opposite, have been completely disproved by ex- 

 periments in which unilateral castration has been 

 carried out without any effect on the antlers at all. 

 In birds, however, a few cases have been recorded by 

 competent observers with a definiteness of detail 

 which leaves no possibility of doubt. One of the 

 more recent of these is that of a pheasant of the 



