158 Heredity and Eugenics 



concerning the influence of altered body states in producing 

 germinal variations. 



It will not do to dodge the issue as to experimental 

 methods by the citation of experiments where these precau- 

 tions have not been taken and say, What matters it, the end 

 result is the same — a modification ? True, a modification, 

 inheritable, has resulted in so many series of experiments 

 that there no longer are any doubts thereon. But that 

 does not and cannot answer the important theoretical 

 question because experiments have all too often not been 

 properly oriented and guarded. In this there is a direct 

 experimental proof of the main contention of Lamarck 

 and C. Darwin, that incident conditions produce permanent 

 modifications. Naturally, in order to be permanent, any 

 departure from the normal must become a part of the 

 germinal constitution — a process which Lamarck never 

 attempted to explain, and of which C. Darwin offered 

 only a formal explanation in his provisional h}^othesis of 

 pangenesis. 



I have attempted to obtain what I considered reliable 

 data upon this mooted point in the inheritance of somatic 

 modifications, and one example of the results obtained when 

 the procedure outlined has been followed may be given. 



To determine whether col oration changes in the soma produced as the result 

 of changed enmronmental conditions are inherited, increased, or 

 dropped in successive generations. 



Conditions. — Temperature on the average 6° C. and relative humid- 

 ity 10 per cent above that in nature, with other conditions natural. 

 These conditions were planned to produce melanic tendencies in 

 variation. 



Apparatus. — Shown in diagram in Fig. 59. 



The experiments in this series were conducted in the years 1900 to 

 1904, and were carried through ten lineal generations. The conditions 

 of temperature and moisture were as follows. 



