Pulmonary tuberculosis and its complications, with special reference to diagnosis and treatment : for general practitioners and students / by Sherman G. Bonney ... With 189 original illustrations, including 20 in colors and 60 X-ray photographs.

  • Bonney, Sherman G. (Sherman Grant), 1864-1942.
Date:
1908
Catalogue details

Licence: In copyright

Credit: Pulmonary tuberculosis and its complications, with special reference to diagnosis and treatment : for general practitioners and students / by Sherman G. Bonney ... With 189 original illustrations, including 20 in colors and 60 X-ray photographs. Source: Wellcome Collection.

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

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    the microorganism is exposed to the direct rays. It is much more resistant to cold, however, and is claimed by some to retain its vitality after freez- ing. The period of retention by bacilli of their pathogenic virulence under various external conditions has been the subject of much experimental observation. VVhUe the testimony of several workers in this field of research, which is possessed of so much practical interest, is somewhat conflicting, there seems to be, on the whole, a fairly uniform belief in the approximate duration of its vitality under similar conditions. In 1869 VUlemin determined the retention of virulence in sputum after several weeks. SchUl and Fischer found that bacilli contained in dry sputum preserved their vitality for six months, but rarely longer. Other observers have found the vitality to vary within wide limits under differ- ing conditions. Some report a loss of virulence after two or three months at most, and others not until after nine months. Cornet assumes that, under orcUnary circumstances, the vitality is destroyed in about three months, and that a retention of pathogenic power for a period of six | months is exceedingly rare and occasioned only by the existence of extraordinary conditions. It is evident that the lack of uniformity of results is attributable to essential differences in the conditions to which the sputum is subjected, viz., the thickness of the layer, the exposure to the sun or to diffused sunlight, and the degree of moisture and wind as determined by seasonable changes. In this connection it is reasonable to assume that if destruction of growth and vitality ensues as a direct result of fundamental attributes of weather, including sunshine, degree of moisture, air movement, etc., important differences inevitably must accompany the climatic conditions under which the experiments are conducted. In other words, if sunshine and dryness are essential factors to overcome the vitality of the bacilli, widely varying results should be reported during seasons when rains do not prevail and in localities where sunshine is almost continuous. To this end the experiments of Gardiner, of Colorado Springs, at an altitude of 6000 feet, are of con- siderable interest. Gardiner exposed to the direct rays of the sun, sputum from a tuberculous patient containing bacilli of established virulence. The sputum remained for varying periods upon sandstone and wood. It was found that a hard, superficial crust formed in the process of drying, and that it was impossible to detach even minute quantities from this surface with the blow-pipe. Actual grinding of the crust was required in order to produce distribution of the bacilli. After one and three-quarter hours of exposure the sputum was rubbed up with sterilized water and inoculated into guinea-pigs, with positive results in one case. It is noteworthy, however, that the portion selected for inoculation was taken from a mass of over two drams of unsmeared sputum, the upper surface of which had hardened into an impermeable crust. Ransome and Delephine had previously conducted an elaborate series of experiments which showed the preponderating influence of direct sunshine as a destroyer of bacillary activity. Sputum exposed to light (not direct sun's rays) and air for forty-five days did not pro- duce tuberculosis after inoculation of rabbits. An exposure to air without sunlight during the same period was insufficient to destroy the power of transmitting the disease. Guinea-pigs were found to respond positively to sputum exposed to air in dark places, but neg- atively if the sputum had been subjected to diffused light as well as air