Page:Science vol. 5.djvu/292

 THE RELA TIONS OF MICROBES TO LIFE.

Owing to Ihe fact that some microacopic organiBins have been shown to play au impor- tant part in many forms of disease, we are somenhat ia the habit of looking upon such organisms in general as our enemies, forgetting many useful purposes ivhicli they serve. One of the most important processes taking place on the surface of the globe is the destniction of such organic masses as have been the seat of life, but which have snfTered death. We have only to think for a moment what the re- sult of a stopping of this destructive process would be, in order to gain a vivid impression in regard to its importance. The living thing can resist the dcBtructive forces. When life ceases, the resisting- power is gone; and, how- ever comples the materials may be of which the organism is made up, thej' are quickly con- verted into simple and stable substances. The chief products of the changes are carbon di- Oiside, water and ammonia, all of which are of high importance, as from thejn again, under the influence of hfe, are elahorateil the com- plex materials. Now, we know, thai, in the breaking-down of organic matter after death, microscopic organisms play a principal rflte. They are the efficient scavengers of the earth. They effect the transfer of the oxygen of the air to the substances to be destroyed, and thus convert useless organic matter into that which is useful.

We thus see, that, while there are microbes which cause disease, there aro others constantly at work keeping tlic conditions favorable to life. Kcoently the suggestion has been maile, and by no leas an authority than Pagleur, llint the changes which are involved in the life-pi-o- cess of both plants and animals arc probably inlioutely associated with the activity of what may be Mlled life-microlies, Pasteur read before the Academy of sciences a paper by Dnclsnx, in which some ex|)eriment8 upon the growth of plants in sterilized soils are de- scribed, Duclaux's pajjcr begins thus: "The destruction of the organic matter of the soil by microl)es, and the production of a new vege-

��tation on the soil, are two phenomena whici always accompany one another. Is there auvd necessary connection between them? Throng the labors of Pasteur, we know that microBCO|H beings can only live at the expense of complex* materials elaborati^d by the plant with the aid of chlorophyl. Can the plant develop in the absence of microscopic beiugs? in other woi-ds. can it, without their aid, utilize the organic matter left by the plant which preceded it on the soil?"

With the object of attempting to answer this question, Duclaux experimented upon peas and beans. These were freed from gcims, sown in a soil which was free from germs, and anpplied ■ with organic matter of a kind which one would J naturally exi>eci to be easily assiuitlated. The result was, t!iat after one or two months the organic matter was found to be unchanged, and the plants did not thrive any better than when placed in distilled water.

Pasteur, in commenting on these oxperi-j ments, takes occasion to suggest to Duclauxl an experiment on the r^le which microbes play I in animal hfe. The exj>eriment Is this, hen's egg, from the surface of which all geimsl have been removed, is to be hatched in n ster»l ilized space, fed with sterilized food, and sup-J plied with sterilized air. Pasteur believes that| the result will be that the cbick will not livi Dnd, in general, that life is impossible withoutj the co-operation of micrabes.

We must bear in mind that this is merely i suggestion, and that it rests at present npoqB no experimental evidence. Ksperiments i the kind suggesteii will involve great I and the greatest accuracy. It cannot be de* nied, that, whether the results should prorQ^ favorable or unfavorable to the \iew of Pasteur) J they would be of the highest interest to thft;! chemist and biologist.

��Is- 80 vast a region of country as the ^yp-l tiau Sudan, extending as it does over about I sixteen or eighteen degrees of latitude and as.l many of longitude, wiili iliHiTences of alti-1

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