THE PHYSICAL BASIS OF LIFE 187 



and the like — confer on it an internal structure which controls 

 its properties for years to come. Each jelly, therefore, has an 

 individuality due to the record which it bears of its past. 



Take another case. A vertical rod of wax is bent, first north, 

 then south, then east, then west, and so on. Left to itself, it will 

 quietly work out these movements in the reverse order. It bends 

 first west, then east, then south, then north, and so on. The 

 molecular structure of the wax is such as to preserve a record 

 not only of the fact that it has been moved, but also of the 

 number, direction, and order of the several movements. 



The Faculty of Growth 



If it be true, as some chemists think, that in the process 

 of oxidation there are always two processes more or less con- 

 current — the first one of synthesis, in which bodies of increased 

 chemical complexity are formed by the union of the oxygen 

 and the combustible substance; the second one of analysis, 

 which supervenes only when the synthetic products reach a 

 degree of complexity where they are unstable at the particular 

 temperature and pressure— then, considered in a general way, 

 the processes of assimilation and growth of living matter are 

 exceptional only in the prominence and permanence of the 

 synthetic stage. The living cell, on this view, is like the flame 

 in being an oxygen vortex ; it is unlike it in the extraordinary 

 latency or delay in the advent of the analytic processes. 



The peculiar feature of the living cell, however, considered 

 as a machine, lies in the fact that, of the total amount of energy 

 which it acquires, a fraction is retained and devoted to the 

 increase of its own substance. In other words, it grows. After 

 a while it divides, and the daughter cells are like itself, so that 

 there is not only the power of increasing the bulk of living- 

 matter by growth, but also a directive faculty called heredity, 

 which constrains the new living matter, made from non-living 

 matter, into the pattern of the old. The problems of growth and 

 multiplication can be reduced to their simplest terms only in the 

 case of minute forms like Amoeba, each of which is at once a 

 single cell and an individual. Each individual amongst the 

 higher forms of life is built of countless cells, all of which, with 

 one or two exceptions, are predestined to death. The excep- 

 tions — the true immortals — are chosen from the germ cells. 

 When, however, an Amoeba multiplies, it divides bodily into 



