LIVING MATTER. 3 



to light several highly important facts. It is likely that living 

 matter is a tolerably definite compound of a number of the 

 chemical elements, and it is probably too low an estimate to say 

 that at least six elements must unite in order that life may ex- 

 ist. Moreover, only a very few out of all the elements are able, 

 under any circumstances, to form this living partnership. 



The most significant fact, however, is that there is no loss of 

 weight when living matter is killed. The total weight of the 

 lifeless products is exactly equal to the weight of the living sub- 

 stance analyzed, and if anything has escaped at death it is im- 

 ponderable, and, having no weight, is not material. It follows 

 that living matter contains no material substance peculiar to it- 

 self, and that every element found in living matter may be found 

 also, under other circumstances, in lifeless matter. 



Considerations like these lead us to recognize a fundamental 

 fact, namely, that the terms living and lifeless designate two 

 different STATES or CONDITIONS of matter. We do not know, at 

 present, what causes this difference of condition. But so far as 

 the evidence shows, the living state is never assumed except 

 under the influence of antecedent living matter, which, so to 

 speak, infects lifeless matter and in some way causes it to as- 

 sume the living state. 



Distinctive Properties of Living Matter. Those properties of 

 living matter which, taken together, distinguish it absolutely 

 from every form of lifeless matter, are : 



1. Its chemical composition. 



2. Its power of waste and repair, and of growth. 



3. Its power of reproduction. 



Living matter invariably contains substances known as pro- 

 teids, which are believed to constitute its essential material basis 

 (see p. 33). Proteids are complex compounds of Carbon, Oxy- 

 gen, Hydrogen, Nitrogen, Sulphur, and (in some cases at any 

 rate) Phosphorus. 



It has been frequently pointed out that each of these six elements is 

 remarkable in some way : oxygen, for its vigorous combining powers ; 

 nitrogen, for its chemical inertia ; hydrogen, for its great molecular 

 mobility ; carbon, sulphur, and phosphorus, for their allotropic properties, 

 etc. All of these peculiarities may be shown to be of significance when 

 considered as attributes of living matter. (See Herbert Spencer, Principles 

 of Biology, vol. i.) 



