CHANGES OCCURRING DURING LIFE. 3 



attention to some facts which have led me to conclude 

 that certain phenomena manifested by part of the 

 material substance of which all living things are 

 composed, are peculiar to the living world ; that be- 

 tween the living state of matter and its non-living state 

 there is an absolute and irreconcilable difference ; that, 

 so far from our being able to demonstrate that the 

 non-living passes by gradations into, or gradually 

 assumes the state or condition of, the living, the tran- 

 sition is sudden and abrupt ; and that matter already 

 in the living state may pass into the non-living con- 

 dition in the same sudden and complete manner ; that, 

 while in all living things chemical and physical actions 

 occur, there are other actions, as essential as they are 

 peculiar to life, which, so far from being of this nature, 

 are opposed to, and are capable of overcoming, phy- 

 sical and chemical attractions. And I think the 

 evidence which I shall adduce will prove conclusively 

 that the non-living matter is the seat of the physical 

 and chemical phenomena occurring in living beings, 

 but that the vital actions occur in the living matter 

 only. Moreover, we shall see that this living matter, 

 which exists in every living thing in nature, can be 

 easily distinguished from all matter in the non-living 

 state. 



5. Changes occurring during life. I shall not con- 

 fine myself to the demonstration of the structure of tis- 

 sues which have been removed from the dead body, but 

 shall endeavour to describe what probably takes place 

 during life while these tissues are being developed, 

 are growing, and are acting each in its own peculiar 

 way. And if I fail in my attempt to give, as it were, 

 an account of the life-history of a tissue, I trust I shall 

 at least be able to assign a more definite meaning to 

 the words "life," "living," "vital," &c., than has 

 been done hitherto. It would be presumptuous in 

 me to hope to place on a more sure foundation the 

 science of the living, but I shall do my utmost to 



B 2 



