208 SUMMARY 



341. Modern biologists are accustomed to divide the characters 

 of multicellular living beings into those which are inborn or 

 innate and those which are acquired, and to declare that only the 

 former can be inherited by offspring. They are mistaken. No 

 character, in any real sense, is more innate than any other. The 

 child inherits nothing from his parents. These terms are convenient, 

 inasmuch as they enable us to avoid circumlocution, but they are 

 inaccurate. The true distinction between characters results from 

 the stimuli under which they arise. The so-called acquirements 

 arise under the stimulus of use or injury ; the so-called inborn 

 characters under other stimuli, especially that of nutriment. The 

 true meaning of the statement, that acquirements are not trans- 

 missible, is that the characters which arise under the stimulus of 

 use or injury in the parent are not reproduced in the child under 

 the stimulus of nutriment. This sudden transference of characters 

 from one category in the parent to another in the child certainly 

 never occurs. In the first category they are products of evolution ; 

 if they were reproduced in the second they would be products of 

 miracle. 



342. Offspring resemble their parents, but with minor differ- 

 ences. These differences are due either to differences in the play 

 of stimuli on individuals, or to germinal differences. The latter 

 are termed variations, and on them all evolution is founded. 

 Massive evidence indicates that immensely the greater number of 

 variations are spontaneous. This, in turn, implies that the 

 germ-plasm is highly insusceptible to the direct action of the 

 environment. A close examination of the evidence renders it 

 clear that living beings could not have persisted on earth unless 

 their variations had been spontaneous and their germ-plasm 

 resistant. 



343. Variations are either progressive or retrogressive. Since 

 the general resemblance between parents and offspring is due to 

 the fact that the latter in their own development closely recapitu- 

 late the development of the former, a progressive variation implies 

 a prolongation of the parental development, a complete recapitu- 

 lation with an additional step. On the other hand a retrogressive 

 variation implies an incomplete recapitulation, an abbreviation. 

 Since offspring recapitulate (with variations) the parental develop- 

 ment, they necessarily recapitulate (with interpolated additions 

 and subtractions due to innumerable interpolated progressive and 

 retrogressive variations that occurred in the ancestry) the evolution 

 of the species. It follows that retrogression implies a reversion to 



