A text-book of bacteriology / by George M. Sternberg.

  • Sternberg, George Miller, 1838-1915.
Date:
1896
Catalogue details

Licence: Public Domain Mark

Credit: A text-book of bacteriology / by George M. Sternberg. Source: Wellcome Collection.

    695/748 (page 647)
    present in a living condition on the second day, but no colonies de- veloped after the third day; the typhoid bacillus died out between the fifth and seventh days ; the cholera spirillum was no longer found on the second day. In the meantime the common water bacteria had increased in numbers enormously. Similar results have been reported by Hochstetter and others. Hueppe, in ten experiments in which the typhoid bacillus was added to well water of a bad quality, found that in two no development of this bacillus occurred after the fifth day, while a few colonies developed in the other experiments as late as the tenth day. In these experiments the temperature was comparatively low (10.5° 0.). At a higher temperature the experi- ments of Wolffhiigel and Riedel show that an increase may take place. At the room temperature (about 20° G.) the typhoid bacillus added to distilled water, to well water, and to Berlin hydrant water was still present, in some instances, at the end of thirty-two days. And it was found that in some cases a decrease in the number occurred, then a notable increase, and finally a second diminution. Koch found the cholera spirillum in a water tank at Calcutta during a period of fourteen days, and in his experiments showed that it preserved its vitality in well water for thirty days, in Berlin sewer water for six to seven days, and in the same mixed with faeces for twenty-seven hours only. In the experiments of Nicati and Rietsch the cholera spirillum preserved its vitality in distilled water for twenty days, in sewer water (of Marseilles) thirty-eight days, in water of the harbor for eighty-one days. The numerous experiments recorded by the observers named, and by Bolton, Hueppe, Hoch- stetter, Maschek, Kraus, and others, show that while the cholera spirillum may sometimes quickly die out in distilled water, in other experiments it preserves its vitality for several weeks (Maschek), and that it lives still longer in water of bad quality, such as is found in sewers, harbors, etc. Bolton found that for its multiplication a water should contain at least 40 parts in 100,000 of organic material, while the typhoid bacillus grew when the proportion was considerably less than this—6.7 parts in 100,000. Russell (1891) has studied the bacterial flora of the Gulf of Naples, and of the mud at the bottom of this gulf, collected at various depths up to eleven hundred metres. His investigations show that sea water does not contain as many bacteria as an equal volume of fresh water; that bacteria are found in about equal numbers in water from the surface and in that from various depths ; that the mud at the bottom constantly contains large num- bers of bacteria; that some of the species isolated grow best in a culture medium containing sea water. At a depth of 50 metres the water contained 121 bacteria per cubic