128 THE KINGDOM OF MAN 



proof that such inheritance takes place, which has never 

 been produced, but on Weismann's part by a demon- 

 stration that the reproductive cells of organisms are 

 developed and set aside from the rest of the tissues at 

 so early a period that it is extremely improbable that 

 changes brought about in those other tissues by unac- 

 customed incident forces can be communicated to the 

 germ-cells so as to make their appearance in the off- 

 spring by heredity. Apart from this, I have drawn 

 attention to the fact that Lamarck's first and second 

 laws (as he terms them) of heredity are contradictory 

 the one of the other, and therefore may be dismissed. 

 In 1894 I wrote : 



' Normal conditions of environment have for many 

 thousands of generations moulded the individuals of a 

 given species of organism, and determined as each 

 individual developed and grew " responsive " quantities 

 in its parts (characters) ; yet, as Lamarck tells us, and as 

 we know, there is in every individual born a potentiality 

 which has not been extinguished. Change the normal 

 conditions of the species in the case of a young 

 individual taken to-day from the site where for thousands 

 of generations its ancestors have responded in a perfectly 

 defined way to the normal and defined conditions of 

 environment ; reduce the daily or the seasonal amount 

 of solar radiation to which the individual is exposed ; or 

 remove the aqueous vapour from the atmosphere; or 

 alter the chemical composition of the pabulum acces- 

 sible ; or force the individual to previously unaccustomed 

 muscular effort or to new pressures and strains; and 

 (as Lamarck bids us observe), in spite of all the long- 

 continued response to the earlier normal specific condi- 

 tions, the innate congenital potentiality shows itself. 

 The individual under the new quantities of environing 



