m. 642] YARIATJOX IX BEFRODUCTION 15 



tioii, IS 111 some (lis])ute. Jn these same organisms, eii- 

 viroimiciii.il ;iu( iits may produce changes persisting 

 tliroiiuli iii.iin generations of uniparental reproduction 

 and evi'ii through l)ii)ar('ntal rei)ro(hK't ion, tlie ]>eriod ot 

 persistence depemhiiu' parlK . on the ininiht r ot u'ciicra- 

 tions througli ^vhleh the tirodiiciiiu' au'cnt acted. Ihis 

 sugi»-ests that inherited t-ha raeters as permanent as anv 

 tli<it i\ist might in tiiiK 1). ^o piodiU'(d. In spite of im- 

 ]K)rtant differences ot opinion among investigators, to the 

 reviewer the lacts in iinipareiilal reproduction seem to 

 ])oint more toward the i)ro(hK'tn)n ol evohitionary change 

 b\ the action of the en\ nonmeut on the germ phism than 

 by any of the other methods. In this respect it takes its 

 phice in that modern revival of work on the inheritance 

 of accpiired characters, of which we had so striking an 

 exampk-> this morning, in the account of the dizzy rats 

 and of the inlieritance of tlieir dizziness; though in the 

 studx ot uiiii)arental reproduction nothing has appeared 

 that iiidieales a transfer of somatic characters to the 



REFEREXCES 



