1 86 / LIONEL TAYLER [September 



will only grow on or in certain media. From a purely chemical stand- 

 point, there is therefore nothing in protoplasmic activity which suggests 

 any new element ; that bacteria thrive under certain conditions hut 

 not under others, being dependent on their powers of combination and 

 subject to the laws of chemical change, is consequently easily explain- 

 able. It may, however, be urged that while it is true that bacteria 

 are sometimes influenced by some slight alterations in their environ- 

 ment, they are often capable of standing great extremes in other 

 directions, and in this respect do not resemble unstable and complex 

 chemical compounds ; even this difference, however, does not hold, since 

 there are many chemically complex and unstable compounds which 

 appear relatively stable under certain conditions while they are equally 

 unstable under others. There are, therefore, a set of conditions 

 associated with early primitive life, which, except for the phenomena 

 of fission which Spencer has shown, is, like the other properties of 

 early protoplasm, capable of a physical explanation — are all explain- 

 able by the laws of chemical change, osmosis, diffusion, etc. 



There are, of course, many fallacies to which one is liable in 

 dealing with such a question ; thus the extreme minuteness of the 

 organisms, and our necessarily imperfect knowledge of their life- 

 history and structure make it probable that any present-day explana- 

 tion will be incomplete. 



I only wish to note that this resemblance is likely to be at least 

 partially true. That this apparent closeness of connection between 

 chemical change and bacterial metabolism may appear to future 

 generations less close than it does to us is possible, still the increased 

 knowledge of the higher organisms, the relation of food-supply to 

 bodily exertion, the recent work on digestion, blood-supply, and tissue 

 change, do not lead to a less but a more close chemical analogy ; in 

 any case the inference, as far as the present time is concerned, is in 

 favour of a very close connection between the laws of chemistry and 

 physics on the one hand, and the forms of vital activity on the other. 



Now, as far as this inference has weight, it must tell against 

 climatic modification in favour of climatic and inter-organismal 

 adaptation, inasmuch as chemical elements have definite affinities, 

 enter into definite combinations in fixed proportions ; and as any 

 alteration in a compound, however complex, must proceed along 

 definite lines, it follows that each form or variety of protoplasm, in so 

 far as it is chemical in nature, can only grow and keep active by 

 being fed by certain foods which it can make use of, and by being 

 . under certain conditions more or less favourable to its organisation ; 

 and when a sufficient number of these favourable conditions are not 

 present, the surplus energy of the organism must in time run down, 

 and the organism will die because it cannot utilise other conditions. 



At the commencement of this article I endeavoured to emphasise 

 the importance of keeping in mind the fundamental distinctions 



