12 THE POPULAR SCIENCE MONTHLY 



becomes " indirect equilibration." The discussion of these two prin- 

 ciples is among the most profound of all of Spencer's writings. The 

 subject, so intimately connected with this, of the transmission of ac- 

 quired characters, was not overlooked in the " Principles of Biology," 

 but it was not brought into the foreground until Weismann's " Essays " 

 began to appear, denying its possibility. Spencer, as is known, entered 

 the lists with his paper on " The Factors of Organic Evolution," and 

 continued to reply to Weismann for a number of years. In him the 

 trained biological specialist found a foeman worthy of his steel. Head- 

 ers of these papers on both sides will of course differ in their judgments 

 on the argument according to their cast of mind, but all will admit 

 that Spencer's presentation of the case was able, and to it, as much as 

 to anything else, were due the many notable concessions that Weismann 

 was from time to time compelled to make.^^ 



In the second volume of the " Principles of Biology," devoted 

 mainly to morphology and physiology, Spencer showed that he could 

 play the role of a specialist, but his special studies and illustrations all 

 have a pliilosophic purpose in establishing principles. These, however, 

 belong for the most part to the minor or more special laws of biology, 

 and do not call out the same philosophic powers as the major and more 

 general laws dealt with in the first volume. Perhaps the most im- 

 portant of these laws is what he calls the " antagonism between growth 

 and sexual genesis," which might otherwise be stated as the law that 

 nutrition and reproduction are inversely proportional. The truth of 

 this is known to practical breeders, florists and horticulturists, but 

 not to the general public, and it has some interesting results. 



Spencer lived to revise his " Biology " and introduce into it much 

 of the "Weismann controversy and other features which had not pre- 

 sented themselves clearly at the time the work was originally written. 

 Upon the whole it is a remarkable work. Surprise has often been ex- 

 pressed that trained specialists in biology had rarely or never been able 

 to trip him on any of his statements. This is partly explainable by 

 the fact that Professor Huxley read the proof of a considerable part of 

 the work, but it does not appear that he found much to correct, and 

 we must admit that Spencer possessed a remarkable faculty of ac- 

 curately stating biological facts that he had not himself observed, and 

 a still greater talent for correlating and interpreting them and fitting 

 them into his universal scheme. 



Let us now turn to the " Principles of Psychology." In his 

 " Synthetic Philosophy " Spencer placed it after the Principles of 

 Biology. Although he says little about his reasons for this arrange- 

 ment, it seems clear that he regarded it as the order of evolution. Yet 



" Of. Weismann's " Concessions," Popuxab Science Monthly, Vol. XLV., 

 June, 1894, pp. 175-184. 



