The methods by which the advocates of a purely physical origin of life seek to establish the correctness of their conclusions, are unfortunately not always attended by uniform results in experimentation. They subject their solutions of organic matter to a very high temperature by means of super-heated flasks, the tubes to which are so packed in red-hot materials that whatever air may enter them shall encounter a much greater degree of heat than that indicated by boiling water. At this temperature (100° C--212° F) they assume that all living organisms perish, especially when the solutions containing them have been kept, for the space of fifteen or twenty minutes, at this standard point of heat. But, in the light of all the experiments which have been made in this direction, there is some doubt as to the entire correctness of their assumption. That many, if not most living organisms, perish at a temperature of 100° C, there is little or no doubt; but that there are some which are much more tenacious of life, that is, possess greater vital resistance to heat, is equally unquestionable. M. Pasteur, for instance, mentions the spores of certain fungi which are capable of germinating after an exposure of some minutes to a temperature of 120° to 125° C. (248-257° F), while the same spores entirely lose their germinating power after an exposure for half an hour or more to a slightly higher temperature. Dr. Grace-Calvert, in a paper on "The Action of Heat on Protoplasmic Life," recently published in the proceedings of the Royal Society, asserts that certain "black vibrios" are capable of resisting the action of fluids at a temperature as high as 300° F, although exposed therein for half an hour or more. But none of these crucial tests, however diverse in experimental results, really touch the all-important question in controversy. They all relate either to living organisms, or to the seeds and spores of vegetation, not to living indestructible "germs"--invisible vital units--declared to be in the earth itself.