LIVING MATTER. 3 



results therefore teach us little of the chemical conditions exist- 

 ing in the matter when alive. Analyses, nevertheless, bring to- 

 light several highly important facts. It appears that living mat- 

 ter 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 exist. More- 

 over, 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- 

 itself, 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 dif- 

 ferent 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 assume 

 the living state. 



^5 



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- 

 proteids, which are believed to constitute its essential material 

 basis (see p. 35). Proteids are complex compounds of Carbon, 

 Oxygen, 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 mobil- 

 ity ; carbon, sulphur, and phosphorus, for their allotropic properties, etc. 

 All of these peculiarities may be shown to be of significance when con- 



