DIGESTION AND REGENERATION. 101 



is the nature of the transition from the one into the other, can be 

 more easily imagined than perceived. 



But now let us ask a straightforward question which very nat- 

 urally arises here. Why may not different kinds of animals arise 

 from any decomposed matter? Human digestion makes human 

 flesh out of the decomposed meat of many different kinds of 

 animals ; the simplest form of animal life, the Amoeba, like- 

 wise changes all sorts of decomposed animals into its own 

 substance : so that at one time we may see the simple organ- 

 ization of the Amoeba transformed into the most complicated 

 tissues of the human structure ; and at another we may find 

 the Amoeba preying upon the decaying body of man, and trans- 

 forming it into the simple, crawling, jelly-like mass of its own 

 body ! 



I have now only to refer you to the experiments with the 

 sealed flasks, (page 15,) in order that you yourselves may 

 answer the question as to whether different kinds of animals 

 may arise from any decomposed matter. I will merely recur to 

 one or two points of those experiments in order to reinforce the 

 argument, and to introduce the proofs in proper sequence. You 

 will recollect that by the manner in which the substances were 

 introduced and heated in these flasks, nothing animate could by 

 any possibility have remained in them alive. It was also shown 

 that animals identical with those which developed in the flasks 

 were killed by a temperature far below that of boiling ; whilst in 

 some of the flasks the heat was raised far above boiling, in one 

 instance 38 and in another 95 above the boiling point; and 

 yet, in these two last, as in many other flasks, living organisms 

 were developed in abundance in the midst of the closely sealed, 

 decomposed substance. 



Now as to the nature of these living beings, which were 

 developed in the flasks, I would say that it makes no difference 

 whether they are animals or plants, or both. In either case it 

 indicates the development of life under the sustaining influence 

 of light, the enclosed purified air, and moisture. 



One kind that was frequently developed is the ordinary yeast' 



