1877.] 



the Germinal Particles of Bacteria. 



423 



it can be shown to have derived infectiveness from some particular source 

 of miasma or contagium. 



I now proceed to the second part of my communication, which relates 

 to Prof. Tyndall's serious, but most courteously expressed, criticisms of 

 my experiments on spontaneous generation*. 



The fact that Dr. Tyndall blames me for incautiously vouching for is, 

 " that in boiled and hermetically sealed flasks Bacteria sometimes appear 

 in swarms." Prom multiplied experiments he concludes that this 

 is not true, and infers that I who vouched for it was incautious. 

 The paper referred to was one in which I, as a bystander, gave an ac- 

 count of certain experiments which Dr. Bastian performed in my pre- 

 sence. So far as relates to the fact above quoted, these experiments 

 were, to my mind, absolutely conclusive ; but inasmuch as I was unable 

 to admit with Dr. Bastian that they afforded any proof of spontaneous 

 generation, I followed them as soon as practicable by a series of experi- 

 ments t (the only ones which I myself ever made on this subject), in 

 which I tested the influence of two new conditions, viz. of prolonged ex- 

 posure to the temperature of ebullition, and of exposure for short periods 

 to temperatures above that of ebullition at ordinary pressure. The 

 experiments accordingly consisted of two series, in the first of which a 

 number of retorts or flasks charged with the turnip-cheese liquid (i. e. 

 with neutralized infusion of turnip of the specific gravity 1017, to which 

 a pinch of pounded cheese had been added), and sealed hermetically while 

 boiling, were, after they had been so prepared, subjected to the tempe- 

 rature of ebullition for longer or shorter periods. In the second series 

 the period of ebullition was the same in all cases, but the temperature 

 was varied by varying the pressure at which ebullition took place. 



The conclusion arrived at, as expressed in the final paragraph of the 

 paper, w T as, that in the case of the turnip -cheese liquid the prone- 



* The expressions referred to are the following : — " I have worked with infusions of 

 precisely the same specific gravity as those employed by Dr. Bastian. This I was 

 specially careful to do in relation to the experiments described and vouched for, I 

 fear incautiously, by Dr. Burdon Sanderson in vol. vii. p. 180 of ' Nature.' It will 

 there be seen that though failure attended some of his efforts, Dr. Bastian did satisfy 

 Dr. Sanderson that in boiled and hermetically sealed flasks Bacteria sometimes appear 

 in swarms. With purely liquid infusions I have vainly sought to reproduce the 

 evidence which convinced Dr. Sanderson ... I am therefore compelled to conclude 

 that Dr. Sanderson has lent the authority of his name to results whose antecedents he 

 had not sufficiently examined" (Phil. Trans, vol. clxvi. p. 57). In the abstract of a 

 lecture delivered at the Royal Institution, January 21st, 1876, similar words occur, as 

 also in a letter to ' Nature ' dated February 27th, 1876, in which Dr. Tyndall, after 

 remarking that the experiments of Dr. Bastian, witnessed by me, were too scanty and 

 too little in harmony with each other to bear an inference, suggests that I should 

 repeat them. 



t ' Nature,' vol. viii. p. 141. 



