what air does or does not contain, since I have long ago shown. . . . that boiled fluids can be made to putrefy and swarm with bacteria in closed flasks, from which air and whatever it may contain has been expelled."[1] The same reasoning also obtains in his communication to the Lancet[2] and to Nature.[3] The result is clear. The doctrine of "spontaneous generation" rests upon exceptions for its truth. In rare instances, and in special infusions, bacteria have appeared after prolonged boiling. After a careful sifting of the evidence, the meagreness of the testimony is striking. All that can be fairly taken at all, when justly weighed, if taken altogether, is not equal to the evidence given by Dr. Burdon-Sanderson.[4] But it is well known that, while admitting and publishing the facts, he ignores absolutely Dr. Bastian's inference. And surely this is the truer philosophy. Let it be granted that, by means not now explicable, the germs of bacteria, destructible in filtered infusions at a boiling temperature, are feebly, and at times, able to survive a slight continuation of the boiling-point in infusions containing solid particles without apparent injury—is not that a ground for inquiring the reason why, rather than for inferring "spontaneous generation?" If we can prove that in ninety-nine cases out of one hundred actual germs are destroyed at 212° Fahr.,but that, in exceptional circumstances, the remaining one case yields bacteria after exposure to 212° Fahr. for some minutes, is not that a reason for inferring, and looking for, some protective influence upon the germ, rather than launching into an hypothesis of a new mode of origin?
That the medium in which minute organic forms are subjected to heat exerts an influence on their subsequent deportment I can abundantly prove. I am equally convinced that the death-point of bacteria-germs hovers very near the boiling-point of water—a conviction amply sustained by fact. This being so, the survival, as germs, of some few, amid incalculable myriads, by some accidental protection, is surely possible. So that, indeed, all true work now should be a study of the germ and its properties, and a discovery by patient research of the life-history of the organism.
The valueless nature of mere temperature experiments on such organisms, as tests of their ability to survive, without a knowledge of their life-history, Dr. Bastian, without knowing it, has made sufficiently plain. He gives a brilliant illustration—styled by himself "typical"—of the futility of his own method. Consider the facts.
In our "Researches" on the monads, my colleague and myself made it a special point to institute a series of investigations on the points of temperature which the adults, and the spores, of each form studied could resist. The results were as unexpected as they were remarkable. Only the results can here be stated. Taking the spore--
