The examination of cow's milk for the detection of pathogenic properties / by Sheridan Delépine.

  • Delépine, Sheridan, 1855-1921.
Date:
[between 1890 and 1899]
Catalogue details

Licence: Public Domain Mark

Credit: The examination of cow's milk for the detection of pathogenic properties / by Sheridan Delépine. Source: Wellcome Collection.

Provider: This material has been provided by The University of Glasgow Library. The original may be consulted at The University of Glasgow Library.

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    (4.) The reaction, notwithstanding the large number of bacteria pre- sent in the majority of specimens, was amphoterous in thu'ty-two cases ; in six cases it was acid, and in seven it was alkaHne. (As six out of these seven specimens were sent to the laboratory together, it is probable that the alkalinity was due to some of the alkali used in cleaning the bottles not having been entirely removed by subsequent washing. I may say, however, that all the specimens received in the laboratory had evidently been collected with great care and uniformity of method, and that the inspector whose duty it was to collect the samples had taken all the trouble necessary to obtain clean bottles.) (5.) Notwithstanding the large number of bacteria often present in the milk, the sediment of seventeen samples could be injected into the subcutaneous tissue and the peritoneal cavity of guinea-pigs with- out producing any lesions beyond a slight temporary irritation not interfering with the general health of the animal ; this was ascertained by careful daily observations and weighing in a number of cases. In seventeen other cases marked inflammatory lesions were found at the seat of inoculation or in the lymphatic ganglia connected with the inflamed part, and in many instances the general health of the animal suffered, as indicated by a rapid loss of weight. This illness, however, was temporary, and the animals allowed to live long enough recovered. In a few cases, however, the lymphatic ganglia connected with the seat of inoculation remained large. These enlarged glands differed from tuberculous glands in that they contained no tubercle bacilli, were fleshy, had a brownish red colour, and showed no necrotic areas, clearly visible. A short bacillus could be demonstrated in several of these enlarged glands. Eight of the milks produced intense septic lesions in the shape of acute fibrino-purulent peritonitis or extensive subcutaneous suppura- tions and necrosis. In six of these cases the blood of the heart was examined bacterio- logically, and a bacillus closely resembling the bacillus coli communis was found invariably present; in one of these cases the streptococcus pyogenes was also isolated. The same bacillus, associated or not with the streptococcus pyogenes and the staphylococcus pyogenes aureus, was also isolated from some of the local lesions. The bacillus, after being cultivated in a state of purity for several generations on agar, produced when injected into guinea-pigs a rapidly fatal septicaemia associated with peritonitis, just as when the milk had been injected. alcohol, and stained in various ways. Tubercle bacilli can be beautifully stained by the Ziehl-NeeLsen method, all tlic fat having been dissolved and washed out. The methylene blue brings out tlie cells and bacteria other tlian tlie tubercle bacillus. If such a film be stained directly witli carbol fuchsin, the coagulated proteids occupying the space between the now dissolved fat globules, stain ileei)ly, so that a permanent preparation sliowing the original size of the fat globules can be obtained. Such ])reparations arc not suitable for the study of cells or micro-organisms. If, liowever, before staining with carbol fuclisin tlie specimen is left for a short time in 10 per cent, sulpliuric acid, theproteid layer does not stain any more, and the cells and micro-organisms stain readily. Films of the sediment, cream, and milk half-way between the layer of cream and the sediment were repeateilly examined to ascertain whether the solid impurities were comjdetely forced into the sediment. It was fouml that the sediment contained th(! bulk of tliese e.xtraneous products, but many bacilli, cells, and sometimes even forei-n bodies such as hairs were carried uji by the cream. In two tuberculous cases tubercle bacilli though most abundant in the sediment were also easily demonstrated in the cream • the mtermed.ato layer of separated milk was always freest from all impurities. Hacteria wire naturally much more numerous in specimens which lia.l taken a long time to reach the laboratory and in those that had been exposed to a high temperature than in ti e others s/ecim^s e^amled i' ^^ '^^^''^^''^ bacteria han apecimena examined in spring or summer.