Bacteria, their Nature and Function¹

Abstract

A WELL-KNOWN English writer a short time ago informed the public that Prof, von Pettenkofer, the distinguished veteran in sanitary science in Munich, expressed the opinion that “the atmospheric envelope of this globe is at present in a bacillophil humour.” Expressions such as these have been repeatedly used in one form or another, some more, some less witty; the intention being, of course, to convey an exaggerated impression of the frame of mind of over-zealous enthusiasts. By such expressions more or less distinguished speakers and writers have been enabled to exhibit the smartness of their phraseology. Thus one distinguished professor relieved the anxiety of his students by the jocular observation that idleness and laginess will probably be found to be due to a specific bacillus, while another no less profound writer enunciated that crime and inebriety are probably due to bacilli. With regard to the distribution of bacteria, as well as with regard to their action, we meet with statements which are almost made humorous by smartness of exaggeration. Under the cover of the title “Science Notes,” one of the London papers offered to its readers for breakfast the following palatable dish:—“In a grain of butter you have 47,250,000 microbes; when you eat a slice of bread and butter, you therefore must swallow as many microbes as there are people in Europe.” Here it ought to be stated that a grain of solid matter of London sewage contains only a small fraction of this number of microbes. But leaving these silly exaggerations and those grotesque sayings to their authors for further improvement, it is nevertheless well established that a considerable number of phenomena in nature are intimately associated with bacterial life. The world of bacteria is comparable to an unseen flora which, in variety of character, of activity and importance in the economy of nature, compares with the visible flora, and in its extension and area of distribution is as great as, in some respects greater than, that of the visible vegetable and animal kingdom. Though unpreceived by the unaided eye, this bacterial world forces itself, by its multifarious activity, continually on our attention; it comes into prominence by the vast effects, the slow but far-reaching results which it produces on man, animal, and plant, for good and for evil, in life and in death. Some of these actions I shall have the honour to bring before you this evening, and you will see that while there are bacteria whose actions are undesired and not conducive to the well-being of man or animals, there are others which are of the greatest service both to them and to plants, and are an essential and integral part in the economy of nature.