TUBERCULOSIS. 325 



a spirit lamp or Bunsen burner until the albumen is coagulated. 

 A few drops of filtered carbol-fuschin solution is put on the 

 cover-glass, and held by a pair of forceps over the flame until 

 steam rises for five minutes. Wash in water, and decolorise 

 by 25 per cent, sulphuric acid solution, and then wash in water. 

 Counter stain with aqueous solution of methyl blue, then wash 

 with water, dry over a flame, and mount in Canada balsam. 

 The bacilli will present a bright red colour on a pale blue 

 ground, and occur singly, in pairs, or aggregated in rosettes. 



The bacilli vary in number in different lesions, and have no 

 relation to the magnitude of the growths. Thus in a large 

 nodule very few bacilli will be found after the most careful 

 examination, whilst a smaller one may contain a large number. 

 When the giant cells are numerous the bacilli are gene- 

 rally few in number, many of them having doubtless been 

 ingested by the giant cells. They are easily detected in the ex- 

 pectorations of human consumptives, and in the thick purulent 

 yellow discharge which is sometimes ejected from the mouths 

 of cattle after long and violent fits of coughing, This material 

 coughed into the mangers and upon partitions and walls of the 

 cow-shed is, when dry, diffused through the air inspired by the 

 healthy cattle, and thus becomes one of the great causes of the 

 spread of the disease. 



The transmissibility by inhalation, as well as that by inges- 

 tion and inoculation, has been proved experimentally. The 

 animals experimented upon were compelled in a chamber to 

 breathe, for several hours daily, air in which were fine particles 

 of phthisical expectoration from persons with cavities in their 

 lungs, mixed with water, and rendered into fine particles by a 

 steam atomiser. Dogs alone were used, as they rarely suffer 

 from tubercle. Eleven animals were experimented upon, and all 

 were killed in a period varying from twenty-five to forty-five 

 days, and, with one doubtful exception, presented well-developed 

 miliary tubercles in both lungs, and in most of them tubercles 

 were also found, but to a smaller extent, in the kidneys, and 

 to a still smaller extent in the liver and spleen. Microscopical 

 examination demonstrated the presence of the bacilli. 



These experiments were conducted by Dr. Tappeinier of 

 Meran, and a preliminary account of them led Dr. Max 

 Schottelius to make similar ones, not only with the sputum of 



