The germ theory again.

Date:
1877
Catalogue details

Licence: Public Domain Mark

Credit: The germ theory again. Source: Wellcome Collection.

Provider: This material has been provided by The Royal College of Surgeons of England. The original may be consulted at The Royal College of Surgeons of England.

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    3-4 tr' T^OFM THEORY AGAIN. 717 All that ride ten or li0rs&-Jtf> the taught sides, thlSlfeso is withdra«W Thl?' horse and rider theri^^£^ft' ’on a furious- om which they both return exhausted, in the njidst of the vivats which refund. from ever*' * is now requireu isSdr the fifteen leagues, when owner and receives liis-Saeiia^HIey to trot, but have an easy movement; amt a, man has been known to ride two hundred mjles a day without fatigue, and living only An-dried meat and mate. THE GERM THEORY AGAIN. We have on several occasions alluded to the Germ theory, by which is meant the theory that invisible germs capable of producing animalculas and of spreading disease are constantly floating in the atmosphere—and that the more impure the air the greater are the number of these germs. We revert to the subject, because it is debated in all quarters, and it is as well that our readers should know something of what is causing so much con- troversy. Some surgeons distinguished as operators are great believers in the Germ theory ; so much so, that before beginning, for instance, to cut off a leg, they cause a certain germ-killing liquid to shower like spray near the part operated on; by uThieb, as is alleged, the wound is kept free of anything noxious. Whether there be germs or not, the use of disinfectants in the air is said to be beneficial. Notably the celebrated carbolic-acid plan of Professor Lister has met with marked success, and is practised by the greatest surgeons of our time. But though the air certainly contains something which favours decomposition, it is by no means yet proved that that something is made up of germs. Professor Tyndall has been the principal advo- cate of the Germ theory, and has written some papers strongly in its favour. Professor Bastian takes an opposite opinion. He thinks that living organisms may originate in disease by spontaneous generation. His notions are that if germs are con- tinually floating about in the air, they would drop everywhere and. anywhere alike. This argument applies more forcibly to the fact which Dr Bastian discovered—namely, that he was able to get life in flasks containing inorganic solutions, but that he always failed if such solutions were not made up of salts containing oxygen, hydrogen, carbon, and nitrogen ; that is to say, of the elements of life. If the organisms are really the result of a molecular arrangement of the ‘ mother-liquid,’ we should I expect to find them only in those fluids which already contain the elements necessary for their composition. Three speculations are involved in these experiments: on the one hand, that low ! forms of life do occasionally arise by spontaneous generation; on the other hand, either that the heat which is usually considered destructive of life and germinating power is in reality nothing of the kind; or that Dr Bastian’s experiments were incorrectly performed. _ Since the publication of Dr Bastian’s observa- tions, a very lively controversy has been carried on in scientific quarters between the supporters of the germ theory and of the theory of spontaneous generation. Dr Bastian’s work was conducted with great care and in the presence of some distin- guished authorities. Dr Sanderson, on the other hand, found that upon increasing the heat which is applied to the flasks, no organisms were pro- duced ; but until we have reason to doubt the generally received opinion as to the amount of heat necessary to destroy life, this result may be equally well explained according to either of the two theories. Dr Bastian insists that the organic solutions in his own flasks are not found by him to undergo putrefaction where every precaution is taken for withholding the entrance of air. Thus a simple piece of cotton-wool, which acts as a kind of sieve, will when placed in the mouth of a flask prevent decomposition. Professor Tyndall has invented the most ingenious contrivances for illustrating his views. In one case he employed a chamber the walls of which were covered by a sticky substance. The particles of dust in the air were allowed to collect and adhere to the sides, and the air in the vessel, as shewn by its non- reflection of a beam of light, was rendered com- paratively dustless. Flasks were now introduced, and they remained for a long period free from organisms. On repeating some of these experi- ments this year, however, Professor Tyndall found that many of the infusions which had previously been preserved from putrefaction with ease, were now found, when placed under the same conditions, to swarm with life. Still he refused to believe in - spontaneous generation,’ and preferred to consider that the production of life in his flasks was due to some fault in his experiments, and that the air of the Royal Institution was not so pure this year as it was last. Instead, therefore, of introducing his fluids by means of an open pipette, as he had previously done, he now made use of a ‘ separating funnel,’ and by this means the fluids found their way into the flasks without exposure to the air. The result of these precautions was that no orga- nisms appeared. The objection, however, that we have to find is, that no guarantee can be given that will enable us to ascertain whether the air is really free from particles of organic matter or not. Last year the air was considered to be pure because moteless ; but this year, though moteless, it was found to be impure. Professor Tyndall and his friends are so ex- ceedingly confident in the power of the germs of the atmosphere, that they attribute to their influence every known case of putrefaction; and they do so because they believe that they have proved that whenever the air can be excluded from a putrescible fluid, putrefaction will not take place. But Dr Bastian has succeeded in producing life out of organic infusions from which the air has been excluded, and which have been previously raised by him to temperatures hitherto considered by scientific authority as fatal to life. Thus the question resolves itself into this : What is the exact point of heat which kills the germs of bacteria ? At present we do not know, and we have therefore no right to make any supposition upon this point in favour of either of the two theories. Since Dr Bastian’s experiments were first made public, the holders of the Germ theory have gra- dually raised what we may call the thermal death- point of bacteria, in order to explain away the results of his experiments by the light of their own theory. If Dr Bastian’s fluids did develop life,