No. 642] SEROLOGICAL EE ACTIONS 



effects and functions which characterize the respective 

 tissues are probably the outcome of unequal activities 

 among the same kinds of fundamental protoplasmic con- 

 stituents in differing local environments, the question of 

 prime importance to the student of evolution is liow the 

 properties of these constituents have come to be changed 

 from what they were initially, how they may be altered 

 in the future — in short, the question of the nature and 

 origin of variations. For whatever we may believe about 

 the degree of preformation which exists to-day in tlie 

 mechanism of heredity, it is absurd to assimie that in the 

 simpler primitive protoplasin from which modern forms 

 have evolved tlier-e could ha\'e been genes of the cliar- 

 acteristics of all the organisms now in existence. What- 

 ever individual development may be, we must assume that 

 racial evolution was epigenetic. While dou})tless in a 

 sense man lived potentially in some primitive ]n-otozoan- 

 like creature, actual material antecedents of his existing 

 attributes wore no more present in this ancestral creature 

 than specific determiners for tlie oceans, continents and 

 topographical features of the world to-day were ])resent 

 in the original nebula wliicli ])i-('('('(1(m1 onr solar sv-tcni. 

 The great central ])i'()l>l('ni nf ("Noliilion is Ju-i ilii- xcry 

 one of how the detonnitinl ivc n<'.MiiiniliU i.>n- whirh rxlst 

 in g<M-m-<rlls to-day li.-,Nr b.vn inmi ,>o, Mr]. I.> M,-]. 

 iiito tliis ("i-twliilc primitive protopl;i>ni. ('."rt.-iiii p<.s- 

 Hbiliti^- lM-c(.in,' rcalitii'^ and rnnr,.Miit:un h n 



basis of this rcalily tlic old nuM-lianisni lias in ].:ii-t Lccn 

 altered, or a new mechanism has come into Ixmii- wliidi 

 persists as a part of the established constitntion of the 

 gei-m-cell. 



Before entering upon a discussion ol" wiiethcr oi- in)t 

 any of the remarkable serological nctivitio which have 

 come to light in recent years may br po-Nihl.- m- probable 

 s(uirce'^ of germinal modification^, we iiin>r nvnll bricfly 

 the ovneral natnn- of inmnnn.loizir n-:n-ti<.n^. >on 

 know, forei-n prot.-in>^ nf either plant o,- .-uiinK.! ..ri::in 

 when injeeled <lire.-tl> or in.li re<-t i> _ into the ei n-nh.t hm 



substances to whicii the -eiieiai name ul n „t iIk,,! n > 

 applied. Thus the toxins ot' bactei'ia incite the i)nMluction 

 of antitoxins; the bacteria themselves lead to the pro- 



