12 THE METHODS AND 



formed. When we speak of such qualities as 

 the formation of pigment in an eye, or the 

 development of fibres in a stem, as due to 

 transmitted elements or factors, you will per- 

 haps ask if we have formed any notion as to 

 the actual nature of those factors. For my 

 own part as regards that ulterior question I 

 confess to a disposition to hold my fancy on 

 a tight rein. It cannot be very long before 

 we shall knoiv what some of the factors are, 

 and we may leave guessing till then. Mean- 

 Avhile however there is no harm in admitting 

 that several of them behave much as if 

 they were ferments, and others as if they 

 constructed the substances on which the fer- 

 ments act. But we must not suppose for a 

 moment that it is the ferment, or the objective 

 substance, which is transmitted. The thing 

 transmitted can only be the power or faculty 

 to produce the ferment or the objective 

 substance. 



