!4 BIOLOGICAL LECTURES. 



acting sympathetically at a distance upon other bodies and or- 

 ganizing itself into symmetrical forms, through simply mechan- 

 ical action. 



Most of our knowledge of matter and its properties has been 

 derived from study within the past thirty or forty years, and 

 there is no reason for assuming that all are known and appre- 

 ciated. In every direction, almost, there is good reason for 

 thinking that much will be added, but it is certain that enough 

 is known to quite debar any one at present from dogmatically 

 limiting it. We do not know enough about it to limit it, and 

 what we do know gives no warrant for limits of any sort. 



In all this one might well say that such phenomena as you 

 have described might fairly well be true of inorganic matter or 

 what has been held to be non-living nature, and yet leave the 

 peculiar phenomena of living organic matter yet to be ex- 

 plained. And what are the peculiar phenomena that belong 

 to the living thing and not to the non-living ? Are they the 

 phenomena of spontaneous movement from place to place? 

 Hardly that. Rub up some gamboge in water and examine 

 the particles in the microscope, and they are seen to be in con- 

 stant movement like animalcules, and this they keep up. 

 Scatter a few bits of camphor upon water and watch the move- 

 ments. Each particle swims around upon the surface with 

 surprising velocity, and each one carefully avoids collision with 

 others as if it were alive, and this is kept up until the camphor 

 is disolved or evaporated. A drop of creosote upon a water 

 surface behaves in an equally surprising manner, as do most of 

 the so-called essential oils, each one having some characteristic 

 movements which enable one to identify it by its behavior on 

 a water surface. Some of these are explained as due to evapor- 

 ation, cohesion, or surface tension, and others to molecular ex- 

 changes of energy between the particles and the medium, but 

 these names signify molecular properties and show that it is 

 possible for molecular energy to show itself by just such kinds 

 of movements as living things exhibit. 



Hofmeister, of Prague, has shown to a demonstration that 

 all which has hitherto been considered the elective affinity of 

 the living cell can be explained in the most natural manner in 

 the world by its colloid condition and chemical constitution. 



