§0 Elliot, Inheritance of Acquired Characters. [January 



should begin to vary from its type, no matter what its cause 

 mio-ht be, would almost certainly have those variations extin- 

 guished by interlneeding with typical individuals. A reasonable 

 supposition, why such individuals as above mentioned should be 

 able to perpetuate their variations or acquired characters without 

 isolation, would be that the inflJences producing the characters 

 were so powerful as to extend over and include the majority of 

 the members composing the group affected, and then it would 

 naturally follow that the original type would gradually disappear 

 (the same influences continuing with undiminished force), to be 

 succeeded by the new form, which in its altered condition would 

 be more fitted, as we may believe, to battle with its changing sur- 

 roundings. 



It is perhaps well that, before proceeding farther, I should 

 hei-e explain what I mean by 'type' and 'typical' forms, as those 

 terms will be used by me frequently. Type simply denotes the 

 starting poitzt. Thus an individual first described is the starting 

 point in our literature of what we call a species, with which all 

 subsequently discovered forms are to be compared. The form 

 represented by this individual may not be, and probably is not, 

 the original source from which all its varieties have sprung, but 

 merely, mainly from accidental circumstances, was first brought to 

 our notice. Thus Cyanocitta stelleri is the type of its particular 

 o-roup, and it is customary to compare the allied forms with it. 

 It does not follow that because the bird we recognize under this 

 name was described first, that it was the source from which its 

 races derived their existence, as one of the forms we call sub- 

 species may just as likely have been the origin of all the races, 

 C. stelleri included, but the latter, having been first known, is 

 the starting point or 'type.' 'Typical' is that form which identi- 

 cally represents the type. 



Weismann,* referring to environment, says, "I only know of 

 one class of changes in the organism which is with difficulty ex- 

 plained by the supposition of changes in the germ ; these are the 

 modifications which appear as the direct consequence of some 

 alteration in the surroundings," and he declines to consider the 

 subject in detail because facts of sufficient precision are not known 

 for a final verdict to be pronounced. But it may be seriously 

 doubted if Prof. Weismann has been able to produce more facts 



*E^says, ad ed. p. 99. 



