CHAPTER IV 



CHEMICAL CHARACTERS OF CELL CRYSTALLISATION 

 BYE-PRODUCTS OF CELL MOVEMENT IRRITA- 

 BILITY OR TACTISM 



THE comparison between living bodies and a ma- 

 chine will form the subject of another chapter, but 

 having proceeded as far as we have in the study 

 of the cell it may be wise to pause for a short time 

 and consider in how far the facts narrated in the 

 previous chapters tally with the conditions obtain- 

 ing in inanimate nature and how far the two cate- 

 gories are at variance with one another. 



In the first place it may safely be said that the 

 chemical constitution of living matter, as far as we 

 know it, does not in any way help us to understand 

 its possibilities. As we have seen, we gain an idea 

 of enormous complexity of composition, but that 

 complexity does not begin to be an explanation of 

 the wonderful powers of living matter. There are 

 other highly complicated organic compounds but 

 they do not display any beginning of vital powers 

 nor anything which is on the road thereto, so far as 

 they have as yet been investigated. It is true that 



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