STUDIES ON FERMENTATION. 51 



These experiments on blood and urine which we have just 

 mentioned date from 1863.* Ten years afterwards, in 1873, 

 they were confirmed in an important and striking manner by 

 the results of a very able series of experiments, which were 

 carried out in our laboratory, by M. Gay on, who was formerly 

 a pupil in the Ecole Normale Super ienre. M. Gayon proved that 

 what held good in the case of blood and urine, also held good in 

 the case of the substances contained in eggs. He found that 

 the whites of eggs might be exposed for any length of time to 

 contact with air, as also might the yolks, or the white and yolks 

 mixed, without any putrefactive change or fermentation result- 

 ing, and without the smallest microscopic germ showing itself, 

 the sole condition being that the air must be freed from all 

 organic particles of dust, germs of mould, bacteria, vibrios, and 

 other organisms which it holds in suspension. This was only 

 a part of the important facts brought to light by M. Gayon. 

 Amongst other things, he proved that spontaneous putrefaction 

 in eggs is invariably caused by the development of organized 

 ferments, thereby correcting the opposite statements an- 

 nounced by M. Donne and M. Bechamp, who were led by 

 their observations to believe that the change in eggs took 

 place quite independently of the action of vibrios and 

 niucedines.f 



It is almost superfluous to remark how greatly the results of 

 these experiments on blood, urine, and the components of the 

 egg are opposed to the doctrine of spontaneous generation, as 

 also to most modern theories on the generation of ferments. 

 As long as experiments relating to the question of so-called 

 spontaneous generation were made on heated substances, the 

 advocates of heterogenesis had some grounds for asserting that 

 such materials could not satisfy the conditions of spontaneous 

 life, and that we should obtain different results by using natural 

 organic liquids, which, if exposed to contact of pure air would 



* Pastetje, Comptes rendus de V Acndemie des Sciences, t. Ivi. p. 738, 1863. 

 f Gayon, Comptes rendus de V Academic des Sciences, and AnnaJes 

 Scientifiques de I'Ecule Nornmle Suverieure, 1874-7o. 



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