Appendix. 6g 



may be plane or solid forms, in gaseous or solid state ; and it 

 may be that we have in no case attained any correct conception 

 as to what causes molecular combination ; but, none the less, the 

 effects we know, and their consummate order we know under the 

 name of chemical law. For myself, this is quite enough. I have 

 a profound sense that the cause of chemical action is beyond the 

 comprehension of man and is near to the hand of God, I do 

 not see that the chemist can assume any more responsibility for 

 the construction of molecules in the test-tube than can the biolo- 

 gist for the growth of cells under the microscope. If we could 

 see and measure the molecules, we should doubtless be no nearer 

 the comprehension of their formation than the biologist is to the 

 formation of cells under his inspection. But whatever be the 

 scope of the human mind in chemical science, it is a science that 

 embraces all that we can know of the composition of matter. 

 In living tissue, the elements (which in mixture would be but 

 dust and gases) are combined into certain kinds of matter, and 

 this combination (with transformation) fulfills the definition of 

 chemical union. 



In limitation, it hardly need be remarked that when chem- 

 ical action has formed the molecule it can do no more : it cannot 

 make the cell, or any other structure or coherent mass formed of 

 molecules, any more than the cell-making action can make the 

 molecule. Now, as cohesion and as heat and other actions im- 

 pel or retard or modify chemical action, it seems almost certain 

 to be true that the action of cell organization must impel or re- 

 tard or modify chemical action. We see that red-hot charcoal 

 will, with oxygen, form carbonic anhydride, while cold charcoal 

 will not : the heat is indispensable, but we do not conceive the 

 carbonic anhydride to be a calorific compound. It is a chemical 

 compound, whatever non-chemical actions are essential to its for- 

 mation. And, if it should ever be settled that certain substances 

 can only be formed in living cells, it is submitted that these sub- 

 stances must none the less be accepted and studied as chemical 

 products. 



