ON THE NATURE OF LTFE. 185 



itself growth, in fact is the very thing possessed by 

 no other substance in the world, and which is possessed 

 by all living matter. He has thus here in words 

 leaped across the unfathomable gulf that separates 

 living from dead matter without recognizing it ; and 

 until the difficulty is fairly met, and all vital action 

 referred to some peculiar complex substance in a state 

 of generic unity though capable of infinite specific 

 variety, while all structure and physical and chemical 

 action belong to matter in its ordinary state, the ma- 

 terialist theory of life will be untenable. In short, 

 the physiological units must be all in all for life, or 

 the supposition of them is of no use at all. By other 

 physiologists the existence of different and more com- 

 plex compounds than the proximate principles are 

 spoken of, but in a vague manner; by Hackel and 

 Huxley, as we shall see in a subsequent chapter, but 

 not with the distinct line of demarcation above given. 

 Among others, Ranke says, " The chief constituents of 

 the protoplasm seem to be albuminates in a state of 

 imbibition with water, or still more highly composite 

 stuffs, which, like haemoglobin and vitellin, give rise to 

 -albuminates on their decomposition " (p. 80). 



It may be interesting to say a few words on the 

 possible physical state of the living matter. The fore- 

 going considerations of the development of properties 

 by complexity of constitution have been summed up 

 by Dr. H. Madden, in his brilliant essay, " On the 

 Relation of Therapeutics to Modern Medicine," 1871. 

 Dr. Madden adopts my suggestion of restricting 

 Schwann's word metabolic to designating the atomic 

 constitution of the living matter, and my conclusions 



