OF THE VITAB POWERS. 23 



to speak of entire animals (which, however simple, as 

 worms, are nevertheless supplied with enveloping mem- 

 branes) the newly laid egg, though at first sight merely 

 fluid, on a more careful examination is discovered to 

 consist of different membranes, of the halones, the cica- 

 tricula, &c. 



Humidity is indeed necessary in the living solid for 

 the exertion of vitality. But that vitality exists in the 

 solid, as solid, is proved by the well-known instances 

 of animalcules and the seeds of plants, in which, 

 although long dried, the vital principle is so entire, that 

 they again live and germinate. 



49. With respect to the supposed exclusive vitality 

 of the blood, I candidly confess that no fact has been 

 adduced in its favour since the time of Harvey, which 

 might not, I think, be more easily, simply, and naturally 

 explained on the contrary supposition. 



For example, the incorruptibility of the blood during 

 life, is far more explicable by the perpetual changes 

 which it undergoes, especially in respiration. 



That the blood is the material from which the living 

 solids are produced, is no stronger an argument of its 

 vitality, than the formation of nymphaeae and of so 

 many other remarkable plants would be for the vitality 

 of water. 



It is difficult to comprehend how the coagulation of 

 the lymph of the blood can demonstrate its vitality. 

 The organic formation of this lymph in generation, nu- 

 trition, and reproduction, depends not upon the lymph 

 itself, as lymph, but upon the action of the nisus for- 

 mativus (38) upon it. 



50. Those who formerly contended* that the blood 



* v. c. Dan. Bcrnouilli, De Respiratiom. Basil. 1721. 



" Respi- 



