ON ARTIFICIAL CELLS 127 



trical stimuli, as well as to acid and alkaline re- 

 actions ; and would thus possess another of those 

 physiological qualities which we ascribe to living 

 matter by the action of positive and negative ions. 



We should, by means of such a model, have ob- 

 tained a cell which illustrated, if it did not actually 

 perform, the process of parthenogenesis. 



This brings us at once to the work of Professor 

 Loeb, of California, who by experiments on the 

 artificial fertilisation of the eggs of a sea-urchin 

 has succeeded in getting what virtually amounts 

 to artificial parthenogenesis or cell-division in 

 the egg. 



It was known that subdivision of the egg could be 

 started by immersing it in a strong salt solution. 

 Natural fertilisation is, of course, accomplished by 

 the sperm of the sea-urchin, which forms a thin 

 membrane round the egg when the cell-division 

 commences. Professor Loeb found that, by im- 

 mersing the egg in concentrated salt solution, the 

 film was similarly formed, although the subdivided 

 cells did not live anything like the length of time 

 that those naturally fertilised by the sperm did, so 

 that the artificial subdivisions were degenerated 

 forms, lacking the vigour of the naturally fertilised 

 cells, but nevertheless capable of living for some time. 

 These subdivided eggs developed into larvse which 

 were mobile, and exhibited all the characteristics of 

 living things in their self-action. 



The self-movement does not perhaps mean very 

 much in any case, and it has always seemed to me 



