434 BIOLOGICAL PHYSICS 



order of organic sequence and continuity. For this to 

 ensue, we must confess, it is necessary, so far as yet 

 proved, in all the higher forms of animal life, that two 

 dynamic, as well as two material, entities are necessary to 

 perpetuate life, and that these are prepared, energised, and 

 organised by two sets of organs situated respectively in 

 two separate living organisms, but are liable to wither or 

 to become de- vitalised, and die, unless brought into contact 

 with each other in a specific manner. When these pro- 

 toplasmic elements, already vitalised, coalesce, and with 

 their united energies, produce a unicellular organism, 

 capable of assuming a multi-cellular condition, and of 

 ultimately attaining to a degree of organic development 

 equal to that characterising the parentage from which 

 they originated, barring the influences of environment 

 and improper nutritive supply a new unit will have 

 been added to the long total of highly organised beings 

 capable of continuing the " line of descent " with un- 

 diminished lustre, and, it may be, in increased perfection 

 of development. 



