164 Special General Meeting, [Dec. 15, 



now take an interest in this Institution, who support it and pro- 

 mote its objects, were baptised into science at Tyndall's Christmas 

 lectures. 



It is not for me, in the presence of some of the greatest living 

 masters of physical science, to attempt to define the significance or 

 estimate the value of Tyndall's contributions to natural philosophy. 

 That his researches in magnetism, light, heat, electricity, on ice and 

 water, on the cleavage of rocks, and on the atmosphere as a vehicle 

 of sound, were of great and permanent value I do not doubt, and I 

 trust something will be said about them by those who are well able 

 to appraise them. But I may perhaps be permitted to point out that 

 in that department of science with which I am myself most familiar 

 — namely, biology — Tyndall did signal service. Not only did he 

 expose and snuif out some erroneous observations and fallacious 

 theories as to the spontaneous origin of life, which but for his 

 interference might have done much mischief and retarded progress ; 

 not only did he supply novel illustrations of the truths already 

 demonstrated by Pasteur, but he himself furnished original bacterio- 

 logical observations which must always be thankfully remembered 

 and do infinite credit to his sagacity. Having found that boiling, 

 which completely sterilised infusions in his earlier experiments, 

 subsequently failed to do so, it occurred to him that this might be 

 owing to the presence in the air of his laboratory of bacteria differing 

 from those which he had first encountered in being possessed of 

 spores, capable of resisting the temperature of boiling water — and 

 this view, be it observed, suggested itself to him at a time when the 

 existence of spores in bacteria had not been proved. Then the truly 

 luminous idea struck him that if his surmise were correct, thorough 

 sterilisation might be effectually secured if the infusions, instead of 

 being subjected to a single boiling, however prolonged, were sub- 

 mitted to a series of boilings of short duration on successive days. 

 He calculated that the first boiling would prove fatal to the bodies of 

 the full-grown adult and reproductive bacteria, although it might 

 not prove destructive of the more resisting spores, and he further 

 calculated that the products of the germination of these spores 

 would not have time in a single day to grow to reproductive maturity 

 and produce spores of their own, so that the second boiling would 

 destroy all the bacteria that had resulted from the sprouting of the 

 original spores in the interval. And, further, he surmised that 

 although all the spores present at the outset might not germinate 

 in the first twenty-four hours, yet all might be expected to have 

 done so within a few days, and thus, that in no long time, the daily 

 boilings would have abolished the entire generation of bacteria, and 

 rendered the solution absolutely and permanently sterile. The result 

 corresponded exactly with Tyndall's anticipations, and so he not 

 only added to the natural history of bacteria by giving grounds 

 for believing them to form spores, but devised the simple and 



