THE GENESIS OF LIFE. 165 



Spallanzani, who was appointed to the professorship of 

 natural history in the University of Pavia in 1768. A man 

 of wide scientific as well as literary culture, Spallanzani was 

 eminently qualified to undertake a series of independent 

 researches in connection with a subject which had, previously 

 to Xeedham's experiments, engaged his attention. Ac- 

 cordingly, we find him preparing to investigate the subject 

 in an independent fashion, his initiatory work being devoted 

 to a practical criticism of the experiments of Needham. It 

 is evident that Spallanzani was duly impressed with the ideas 

 of Redi, and with the assertion that, judging from all the 

 analogies presented by nature at large, living things could 

 originate only from pre-existent vitality. But to meet the 

 counter-assertion and experimental facts of Needham, evi- 

 dence of like nature was required ; and we find Spallanzani 

 setting to work to institute a series of investigations, the 

 method of which exhibited a decided improvement on that 

 of Needham. The vessels employed by the Abbe to contain 

 the fluids or infusions to which the tests were to be applied, 

 were provided with slender necks, so that the aperture of 

 each vessel could be readily and hermetically sealed by fusing 

 the glass. Contrasted with Needham's method of merely 

 corking and sealing his flasks, the Abbe's plan appears 

 immeasurably superior and exact ; and, as the results proved, 

 such a belief is fully warranted. Spallanzani, it must be 

 remarked, exposed his fluids to much more rigorous condi- 

 tions in the matter of heat, than those to which Needham 

 subjected his infusions. The Abbe' kept his fluids at the 

 boiling-point for periods varying from half an hour to three- 

 quarters of an hour ; thus placing the possibility of destroy- 

 ing any contained life on surer and more feasible grounds 

 than that afforded by Needham's shorter period of exposure 

 to a lower temperature. The results of these experiments 

 fully justified the expectations of Spallanzani. Allowed to 

 stand for varying periods of time, the liquids in his flasks 

 remained perfectly clear, and when examined by the micro- 

 scope gave no indications of life. Therefore, argued the 



