SPONTANEOUS GENERATION. 571 
floating matter, and while doing so I was surprised to 
notice that, at the ordinary rate of transfer, such matter 
passed freely through alkalis, acids, alcohols, and ethers. 
The eye being kept sensitive by "darkness, a concentrated 
beam of light was found to be a most searching test for 
suspended matter both in water and in air a test indeed 
indefinitely more searching and severe than that furnished by 
the most powerful microscope. With the aid of such a 
beam I examined air filtered by cotton-wool; air long kept 
free from agitation, so as to allow the floating matter to 
subside; calcined air, and air filtered by the deeper cells of 
the human lungs. In all cases the correspondence between 
my experiments and those of Schroeder, Pasteur, and 
Lister in regard to spontaneous generation was perfect. 
The air which they found inoperative was proved by the 
luminous beam to be optically pure and therefore germless. 
Having worked at the subject both by experiment and 
reflection, on Friday evening, January 21, 1870, 1 brought 
it before the members of the Royal Institution. Two or 
three months subsequently, for sufficient practical reasons, 
I ventured to direct public attention to the subject in a 
letter to the Times. Such was my first contact with this 
important question. 
This letter, I believe, gave occasion for the first public 
utterance of Dr. Bastian in relation to this subject. He 
did me the honor to inform me, as others had informed 
Pasteur, that the subject " pertains to the biologist and 
physician/' He expressed " amazement " at my reasoning, 
and warned me that before what I had done could be 
undone " much irreparable mischief might be occasioned." 
With far less preliminary experience to guide and warn 
him, the English heterogenist was far bolder than Pouchet 
in his experiments, and far more adventurous in his con- 
clusions. With organic infusions he obtained the results 
of his celebrated predecessor, but he did much more the 
atoms and molecules of inorganic liquids passing under 
his manipulation into those more " complex chemical 
compounds/' which we dignify by calling them "living 
organisms." * As regards the public who take an interest 
* ' It is further held that bacteria or allied organisms are prone to 
be engendered as correlative products, coming into existence in the 
several fermentations, just as independently as other less complex 
chemical compounds." Bastiau, Trans, of Pathological Society, vol. 
xxvi., 258. 
