8 ELEMENTS OF BIOLOGY. 



It seems certain, then, that no body is capable of niani- 

 festing the marvellous phenomena of life, unless it be com- 

 posed of some form or other of albuminous or protoplasmic 

 matter. We know, at any rate, of no such body at present, 

 and we are therefore justified in asserting that the presence 

 of an albuminous basis is an essential condition of vitality. 

 Most naturalists probably would subscribe to this state- 

 ment ; but there are two different senses in which it would 

 be received. Some eminent authorities insist that albumin- 

 ous matter or protoplasm is not only a condition of vitality, 

 but that it is its cause ; or, in other words, that life is one 

 of the properties of protoplasm. It is asserted, namely, 

 that life is the result of the combined properties of the 

 elements which form albuminous matter, just as the proper- 

 ties of water are the resultant of the combined properties 

 of its constituent hydrogen and oxygen ; and it is alleged 

 that it is just as absurd to set down the phenomena of life 

 to an assumed '' vital force," as it would be to ascribe the 

 properties of water to an assumed " aquosity." On the 

 other hand, equally eminent philosophers would assert that 

 the view just mentioned is one which confounds effect with 

 cause, and that albuminous matter is at best but a conditio7i 

 of vitality, just as the presence of a conductor may be said 

 to be an essential condition of electricity. The question 

 as to which of these two opposing views has most in its 

 favour is one of sufficient importance to warrant a brief 

 exposition of the grounds upon which a decision may be 

 arrived at. 



In the first place, when we come to sum up the actual 

 data upon which such a decision should be formed, it is 

 clear that we know two factors only of the case. We recog- 

 nise certain phenomena which we call " vital," as being 

 exclusively manifested by living beings. We recognise, 

 further, that these phenomena are never manifested except 

 by certain forms of matter, or, it may be, by but a single 

 form of matter. We conclude, therefore, that there must be 



