EXPERIMENTAL IMITATION OF PliOTOPLASMIC MOVEMENT. 103 



seems to me that by heating ordinary olive oil to 80° — 90° C. 

 for twelve or twenty-four hours, a suitable medium may be 

 obtained. 



Finally, I would like to remark that I am the last person to 

 defend the view that these drops, exhibiting protoplasma-like 

 movements, are directly comparable to protoplasm. Composed 

 as they are of oil, their substance is entirely different from 

 protoplasm. They may be, however, compared with the latter, 

 in my opinion, firstly with regard to their structure, and 

 secondly with regard to their movements. But as the latter 

 depend on the former, we may assume that the amoeboid 

 movement of protoplasm itself depends on a corresponding 

 physical constitution. 



These drops, too, resemble organisms inasmuch as they 

 continue for days to exhibit movements, due to internal 

 causes, which depend on their chemical and physical structure. 

 I do not believe that up to this time any substance has 

 been artificially prepared which in these two points, viz. 

 structure and movement, has so much resemblance to the most 

 simple form of life as have these vesiculate drops. I hope, 

 therefore, that my discovery will be a first step towards 

 approaching the problem of life from the chemico-physical 

 side, and towards passing from vague and general hypotheses 

 of molecular constitution to the surer ground of concrete 

 conceptions of a physical and chemical nature. 



It is, however, a special satisfaction to me to hear that in 

 your country, which has given rise to so many and so cele- 

 brated men in biological science, my investigations are followed 

 with interest and sympathy. 



With friendly greetings. 



Yours sincerely, 



O. BiJTSCHLI. 



