OF LIFE 206 



Conditions essential to the Existence of the Order and 

 Structure of a Body in order that it may possess Life. 



First condition. No body can possess life unless it consists essentially 

 of two kinds of parts, viz. supple containing parts and contained 

 fluid substances. 



As a matter of fact, no body that is perfectly dry can be alive, 

 nor can any body whose parts are fluid be in possession of Ufe. The 

 first condition essential to life in a body therefore is that it should 

 consist of a mass with two kinds of parts, the one solid and containing, 

 but soft and more or less cohesive, the other fluid and contained. 



Second condition. No body can possess life unless its containing 

 parts are cellular tissue or formed out of cellular tissue. 



Cellular tissue, as I shall show, is the matrix in which all the organs 

 of living bodies have been successively formed ; and the movement of 

 fluids in this tissue is the means adopted by nature for the gradual 

 creation and development of these organs. 



Every living body is thus essentially a mass of cellular tissue in which 

 more or less complex fluids move more or less rapidly ; so that if the 

 body is very simple, that is, has no special organs, it appears homo- 

 geneous and consists only of cellular tissue containing fluids which are 

 slowly moving ; but if its organisation is complex, all its organs with- 

 out exception are invested in cellular tissue down to their smallest 

 parts, and are even essentially formed of it. 



Third condition. No body can possess active life except when an 

 exciting cause of its organic movements works within it. Without 

 the impulse of this active stimulus, the solid containing parts of an 

 organised body would be inert, the contained fluids would remain 

 at rest, organic movements would not take place, no vital function 

 would be carried out, and consequently active life would not exist. 



Now that we know the three conditions essential to the existence of 

 life in a body it becomes easier for us to ascertain wherein consist 

 the order and state of things necessary to a body for the maintenance 

 of life. 



For this purpose, we must not limit our enquiries to living bodies 

 with a highly complex organisation ; for we should never learn from 

 them to what cause life is to be attributed, and we might select at 

 hazard factors of no fundamental importance. 



But if we fix our attention on that extremity, either of the animal or 

 plant kingdom, in which are found living bodies with the simplest 

 organisations, we shall notice, in the first place, that in each individual 

 the body consists only of a gelatinous or mucilaginous mass of cellular 

 tissue of the feeblest coherence, the cells of which are in communication. 



