220 ZOOLOGICAL PHILOSOPHY 



M. Richerand, however, who has in particular developed this opinion 

 in the prolegomena of his Physiologie, admits that the sensibility, 

 which gives us the power of receiving sensations and depends on 

 nerves, is not the same thing as that more general kind of sensibility 

 for which no nervous system is necessary. For the former he suggests 

 the name of perceptibility and for the latter that of latent sensibility. 



Since these two faculties are different in their origin and results, 

 why should we give a new name to the phenomenon, long known as 

 sensibility, and transfer the name of sensibility to a more recently 

 observed phenomenon of altogether special nature ? Surely it is more 

 convenient to give a particular name to the general phenomenon on 

 which life depends : and this is what I have done by calhng it orgasm. 



It is probable that without orgasm (latent sensibihty), no vital 

 function could go on ; for wherever it exists, there can be no true 

 inertia in the parts ; they are no longer merely passive. This is the 

 element of truth in the idea that all the living parts feel and act in 

 their own way, that they distinguish among the fluids which bathe 

 them whatever is suitable for their nutrition, and that they separate 

 from them those substances which affect their special type of sensi- 

 bility. 



Although we are not definitely aware how each vital function is 

 performed, we should not gratuitously attribute to the parts a know- 

 ledge and power of choice among the objects which they have to 

 separate out, and retain or evacuate. We should rather reason thus : 



L The organic movements aroused are simply due to the action 

 and reaction of the parts ; 



2. From these actions and reactions it follows that the state and 

 nature of the parts undergo alterations, decompositions, new com- 

 binations, etc. ; 



3. As a result of these alterations, there occur secretions which 

 are favoured by the width of the secretory canals ; depots are estab- 

 lished which are sometimes kept isolated and sometimes attached to 

 these same parts ; lastly, there are various evacuations, absorptions, 

 resorptions, etc. 



All these operations are mechanical and subject to physical laws ; 

 they are carried out by means of the exciting cause and of orgasm, 

 which keeps up the movements and activities ; so that by these means 

 and by the shape, arrangement and situation of the organs, the vital 

 functions are varied and controlled, and each works in its special 

 way. 



The orgasm dealt with in this chapter is a definite fact, which what- 

 ever we call it can no longer be neglected. We shall see that it is 

 very weak and faint in plants where its powers are very limited, but 



