428 MEMOIRS OF THE NEW YORK BOTANICAL GARDEN 



Significance of serum incompatibilities, etc. — It would seem that 

 a clue to the processes involved in sterility due to physiological 

 incompatibility might be found in the interactions between the 

 tissues and the body fluids of different individuals as exhibited 

 in the results of tissue grafting, in infection and immunity, and in 

 hemolysis and isoagglutination. Such suggestions have been 

 made especially by Jost ('07), Compton ('12, '13). Morgan ('10), 

 and by Lillie ('13). 



In tissue grafting, both in animals and plants, the degree of 

 success depends on close relationship, and there are no evidences 

 that in grafting there is any sort of tissue incompatibility com- 

 parable to that exhibited in self-sterility or in cross-sterility be- 

 tween closely related indi\iduals. Here the results seem to 

 present no analogies unless it can be shown that tissue grafting 

 in the animals and plants which show self- and cross-sterility 

 behaves differently from the rule and shows the same limitations 

 as the fertilizations. 'Fhis is a possibility, and in the absence of 

 all evidence on this point must be held as such, although it should 

 be noted that the self-incompatibility exhibited in cases of sterility 

 in hermaphrodites is not indicated by any incompatibility of purely 

 vegetati^•e parts or e\-cn in general debility or decreased vegetative 

 vigor. 



From the nature of the processes of fertilization in higher plants, 

 it would appear that, as Jost ('07) has pointed out, any stimu- 

 lating or inhibiting substances operating in the interrelations of 

 the tissues inxolved must be diffusible and must be products of 

 the cells involved. If this be true, the data regarding the incom- 

 l)alil)ilit\' of normal l)od\- fluids of different indixiduals, as ex- 

 hil)iled by the phenomena of agglutination, cytolysis, and pre- 

 cipitation should l)e studied with reference to its bearing on the 

 phenomena of self- and cross-sterility. In agglutination phe- 

 nomena, which have a distinct value in the clinical diagnosis of 

 infectious diseases, we see the visible effects of various types of 

 so-called antigen-antibody reactions constituting a type of reac- 

 tion between two organisms. E\en in interspecific relations, 

 howe\er, there are exceptions to any general rule of operation: 

 group reactions show that, even in sharply defined species, specificity 

 may not exist; " no two strains of bacteria of the same species are 

 exactly similar in (heir agglutinabilitN in the same serum" (Zinsser 



