CRUSTACEA AND MOLLUSCS 233 



precisely in this looser texture that we find the centre 

 of gravity of the whole life. 



The living substance has distinctive properties which 

 we call the phenomena of life, and which are familiar 

 enough to everyone as nutrition, movement, irritability, 

 and so on. When these properties disappear we say 

 that the organism is dead. 



All the vital phenomena, however varied they may 

 be, are based on one property of the living matter, 

 namely, its interchange or circulation. The funda- 

 mental quality in this is " metabolism " ; that is to say, 

 the living substance breaks up of itself unceasingly and 

 regenerates itself, and in doing so thrusts out matter 

 from itself and takes in new matter from without. As 

 it is the living albuminoids that behave in this way, we 

 may say : Life consists in the metabolism of the biogens. 



This metabolism ceases when life has left the body. 

 We have, in fact, every reason to believe that the 

 metabolism is suspended in "sham death," even when 

 it is voluntary, as in the case of the Indian fakirs. 

 The trance or simulated death of the fakir may last 

 for six weeks. Many of the animals, also, fall every 

 year into an apparent death-condition, and awake to 

 new life in proper conditions. The seeds of plants 

 may lie for years without vital functions, yet germinate 

 when they are put in moist earth. The very finest 

 methods have failed to detect any trace of giving-off 

 matter in these seeds. But it is untrue that the 

 grains of wheat taken from Egyptian tombs thousands 

 of years old grow into plants. They decay when they 

 are put in water. 



