14 THE CASE AGAINST EVOLUTION 



stitute the organism of the individual) is registered in the germ 

 cells (which constitute the vehicle of racial inheritance), is 

 supported neither by a priori probability nor by any facts 

 of observation. Germ cells give rise by division to somatic 

 or tissue cells, but the converse is not true ; for, once a cell has 

 become differentiated and specialized into a tissue cell, it can 

 never again give rise by division to germ cells, but only to 

 other tissue cells of its own kind. Hence the possibility of a 

 change in the tissue being transmitted to the germ has no 

 antecedent probability in its favor. Neither is it grounded 

 on the facts of observation. Bodily mutilations of the 

 parent are not transmitted to the offspring. The child of a 

 blacksmith is not born with a more developed right arm than 

 that of a tailor's child. When the ovaries from a white rabbit 

 are grafted into a black rabbit, whose own ovaries have been 

 previously removed, the latter, if mated to a white male, will 

 produce spotlessly white young. Hence the offspring inherit 

 the characters of the germ track of the white female, whence 

 the ovaries were derived, without being influenced in the least 

 by the pigmented somatic cells of the nurse-body {i.e. the 

 black female), into which the ovaries were grafted. Kam- 

 merer's experiments, in which young salamanders were found 

 to exhibit at birth the coloration, which their parents had 

 acquired through the action of sunlight, fail to convince, be- 

 cause, in this case, the bodies of the parents are not suflSciently 

 impervious to light to preclude its direct action upon the ga- 

 metes while in the reproductive organs of the parents. Hence 

 we cannot be sure but that the coloration of the offspring de- 

 rived from these gametes is due to the direct agency of sun- 

 light rather than to the intermediate influence of the modified 

 somatic cells upon the germ plasm. 



The same objection holds true of the recent experiments, 

 in which the germ cells have been modified by modifying the 

 interior medium or internal environment by means of anti- 

 bodies and hormones. No one doubts the possibility of influ- 

 encing heredity by a direct modification of the germ cells, espe- 



