6 BIOLOGICAL LECTURES. 



every living thing in our experience consists of a mass of ordi- 

 nary matter, and we have no experience of any living thing not 

 so embodied. From mammoth to monad there are the same 

 elements combined. Evidences of life are of various sorts, but 

 generally they consist in movements of some kind, which may 

 be locomotive, or such as involve maintenance of functions of 

 nutrition, temperature, and so on, in animals; but in plants of 

 the higher types there is apparently only maintenance of nu- 

 trition and reproductive functions. In seeds and eggs, there 

 is somehow the presence of life without any of the obvious 

 evidences. Take a hen's egg for instance. Is it alive, or 

 shall we ask, is it capable of living.^ Two very different 

 questions. If it be kept at the temperature of 104° for 

 three weeks, the most wonderful transformation takes place, 

 and out of the albuminous mass has grown a thing with curi- 

 riously adapted organs and endowed with intelligence so it can 

 take care of itself. If on the other hand the same egg had 

 been heated to 150° for five minutes, or cooled to 32°, all pos- 

 sibility of growth would have been stopped. What difference 

 can temperature have on life } 



What is temperature } Physically it is atomic vibration and 

 is measured by its amplitude. How does atomic vibration 

 affect the conditions of matter } It permits different combina- 

 tions at different degrees, so one would infer that the egg 

 molecules were chemically disrupted by considerable changes 

 in temperature. But if the Q^g had other qualities not physico- 

 chemical in nature or necessarily related to them, what be- 

 comes of them when there is a change of temperature } Put 

 the same egg away for two or three months, and then it is 

 found to be as unable to grow into a chick as if it had been 

 boiled. What now has taken place — chemical disorganization 

 as before. A grain of corn can stand a much wider range of 

 temperature, and maintain its ability to grow under appropriate 

 conditions of warmth and moisture, and this too for a much 

 longer time, some years; but it slowly deteriorates and in a 

 few years with the best of care it loses — what } its life } 

 Does it really have life until it begins to grow t Let that 

 process once begin and it cannot be arrested. It must con- 



