A manual of bacteriology, clinical and applied / by R. Tanner Hewlett.

  • Richard Tanner Hewlett
Date:
1918
Catalogue details

Licence: In copyright

Credit: A manual of bacteriology, clinical and applied / by R. Tanner Hewlett. Source: Wellcome Collection.

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    the higher plants in ordinary circumstances are unable to obtain nutriment unless the complex compounds, pro- teins, urea, and other nitrogenous bodies, which form the important constituents of many manures, are broken down into simpler ones through the agency of bacteria. He sowed seeds in sterile soil free from nitrates, nitrites, and ammonia, which was plentifully watered with sterile milk and solutions of sugar and starch. No changes occurred in these substances, the seeds lost weight, and the seedlings dwindled and died. As regards the higher animals various views have been expressed. Pasteur considered that their life also would probably be im¬ possible without the presence of bacteria in the intestinal tract. Nencki expressed the opinion that this idea of Pasteur’s was an erroneous one, and his experiments in conjunction with Macfadyen and Sieber 1 showed that any considerable decomposition of the food by bacteria first takes place in the large intestine, and that the digestive juices alone, without the co-operation of bacteria, are able to prepare the constituents of the food for absorp¬ tion. Nuttall and Thierfelder obtained unborn guinea- pigs by Caesarian section with antiseptic precautions, and afterwards kept them in a sterile environment and fed them on sterilised food. Not only did the animals live, but they were even in a more thriving condition than those naturally brought up. The intestinal tract was found to be sterile on the eighth day. Schottelius, how¬ ever, found that chickens reared on sterile focd were retarded in development, and experiments by Moro on turtle larvae point to the same conclusion, viz. that intes¬ tinal bacteria are necessary for normal nutrition. On the other hand, Cohendy 2 was able to rear chickens satisfac¬ torily without the presence of bacteria. Levin found 1 Journ. of A?iat. and Physiol., xxv, p. 390. ? Ann. e I’lnst. Pasteur, xxvj, 1912, p, 106,
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