OBJECTIONS TO THE GERM THEORY. 83 



accuracy in the observations. In view of the very wide 

 distribution of the micro-organisnis, and of their 

 relatively great resisting power to noxious agents, it is 

 not easy to devise faultless experiments in which the 

 entrance of organisms into the fermentescible substances 

 will be prevented with certainty. It is only recently 

 that the degree of heat which will kill micro-organisms 

 in all cases has been accurately determined ; and we can 

 now assert definitely that the earlier observers admitted 

 sources of error in that the vessels and utensils employed 

 were not freed from germs adhering to them by exposure 

 to a sufficiently high temperature. Those experiments 

 are of course especially difficult in which exposure to 

 high temperatures, and in fact any alteration of the 

 fermentescible material, must be avoided, in order not to 

 interfere with any possible abiogenesis, or with the power 

 of the chemical ferments. It is only after great practice 

 and many failures that one is able to carry out such a 

 series of experiments with uniform results. If one is 

 contented with a small number of experiments, and is 

 not completely master of the methods, all or the majority 

 of his preparations will without doubt contain organisms, 

 and show putrefaction or fermentation ; and if the sources 

 of error are overlooked, and if it is believed that in 

 every case the precautions were sufficient to exclude 

 micro-organisms, every erroneous experiment will furnish 

 proof of abiogenesis, or of the occurrence of putrefaction 

 without organisms. It is clear that it is only possible 

 to attach weight to such results when they are uniform in 

 all cases and when we are justified in assuming that the 

 experimenter possesses the necessary skill in mycological 

 work. On the contrary, it is known that several investi- 

 gators for example, Marchand, Meissner, and others 

 have obtained a large number of results which support 

 the germ theory; substances of a putrescible nature 

 have been preserved without alteration for years, simply 

 by absolute exclusion of organisms, and indeed an 

 increase in the percentage of successes is distinctly 

 evident in these experiments in proportion to the 

 increasing skill of the experimenter. 



