1 88 THE BEGINNINGS OF LIFE. 



where new living matter is produced during the growth 

 of organisms, this is in part brought about because there 

 is a natural tendency amongst the food molecules to 

 fall into such states of combination however much the 

 particular nature and form of the new matter may be 

 determined by the influence of that which already 

 exists. 



It must be remembered, however, that although many 

 of the processes whereby food is assimilated within the 

 bodies of living things are strictly comparable in nature 

 to processes of fermentation, nevertheless, the precise 

 changes which the elements of the food undergo in the 

 various stages of the process are quite different from 

 those which take place in ordinary fermentations. And, 

 moreover, in the last stage of the process, when food 

 has been reduced to the condition of blood-plasma, the 

 latter is subjected throughout the body to all the special 

 activities of the several tissues, and is formed into 

 as many kinds of living matter, which subsequently, 

 under the influence of c organic polarities,' fashion 

 themselves into the exact likeness of these several 

 tissues *. 



1 In the 'Introduction' of his celebrated 'Regne Animal' (1816), 

 Cuvier made the following notably suggestive remarks, which will be 

 found to be very much in accordance with our present argument. He 

 says : ' Life, then, is a vortex (tourbillon), more or less rapid, more or 

 less complicated, the direction of which is constant, and which always 

 carries along molecules of the same kind, but into which individual 

 molecules are continually entering, and from which they are constantly 

 departing ; so that the form of a living body is more essential to it than 

 its matter. ... As long as this movement subsists, the body in which 



