Page:Popular Science Monthly Volume 6.djvu/201

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189
THERMAL DEATH-POINT OF LIVING MATTER.

Brewer in California; and 208° as observed by Descloizeaux in Iceland." As we have no grounds for criticising these observations, we are bound to look upon them, provisionally at least, as correct and taken with all due care, though it is only fair to add that both Max Schultze and Cohn appear to be not altogether satisfied with some statements of the same kind.[1] Such instances, if thoroughly accurate, may perhaps be taken as examples of the highest temperature which it is possible for living matter to endure, even where it has been inured to its influence in the most gradual manner. And the real point of view from which these facts should be regarded is, indeed, pointed out by Prof. Wyman when he says: "Having become adapted through a long series of years to their surroundings, such organisms may be supposed to live under circumstances the most favorable possible for sustaining life at a high temperature. It is a well-known physiological fact that living beings may be slowly transferred to new and widely different conditions without injury; but if the same change is suddenly made, they perish. In the experiments made in our laboratories, the change of conditions is relatively violent, and therefore liable to destroy life by its suddenness."

3. If we omit, therefore, the facts concerning the existence of living organisms in thermal springs which are altogether peculiar, and which lie outside the boundaries of our present inquiry, all that we know about the unaccustomed influence of high temperatures upon living things can easily be shown to be even more harmonious than it may at first glance appear. We have only to bear in mind two or three general principles in order to be able to harmonize the several experimental results arrived at with the now very generally admitted doctrine as to the oneness or generic resemblance existing between all forms of living matter. We must bear in mind, first of all, the consideration enforced by Spallanzani, that there are different grades of vitality, or, in other words, forms of living matter which exhibit more or less of the phenomena known as vital, and that of these forms those which exhibit the most active life are those which would be most easily killed by heat. Thus we should expect the latent "life" of the germ, egg, or seed, to be less easily extinguished than the more subtile, and, at the same time, more active life of the fully-developed tissue-element or organism; and we should also expect that the vegetal element or organism would, as a rule, be less readily killed than the more highly-vitalized animal element or organism. These principles, based upon the consideration of relative complexity of life, are, however, subject to the influence of a disturbing cause, since we must also take into account, in the case of animals, whether we have to do with the elements of a warm-blooded or a cold-blooded organism, owing to the fact that custom or habitual conditions tend to render the more active tissue-elements of warm-blooded animals better able to withstand the

  1. Max Schultze, "Das Protoplasma," Leipsic, 1863, p. 67.