422 ON THE OKIGIN, PEOPAaATION, 



we have learnt from his first memoir : It is univers- 

 ally recognised that tuberculosis is caused by tubercle 

 bacilli, which reach the lungs through the inhalation 

 of air in which the bacilli are diffused. They come 

 almost exclusively from the dried sputum of consump- 

 tive persons. The moist sputum, as also the expired 

 breath of the consumptive patient, is, for this mode of 

 infection, without danger. If we can prevent the dry- 

 ing of the expectorated matter, we prevent in the same 

 degree the possibility of infection. It is not, however, 

 sufficient to place a spittoon at the disposal of the 

 patient. The strictest surveillance must be exercised 

 by both physicians and attendants, to enforce the pro- 

 per use of the spittoon, and to prevent the reckless dis- 

 posal of the infective phlegm. Spitting on the floor 

 or into pocket-handkerchiefs is the main source of 

 peril. To this must be added the soiling of the bed- 

 clothes and the wiping of the patient's mouth. The 

 handkerchiefs used for this purpose must be handled 

 with care, and boiled without delay. Various other 

 sources of danger, kissing among them, will occur to 

 the physician. A phthisical mother, by kissing her 

 - healthy child, may seal its doom. Notices, impressing 

 on the patients the danger of not attending to the pre- 

 cautions laid down in the hospital, ought to be posted 

 up in every sick-room, while all wilful infringements of 

 the rules ought to be sternly punished. Thus may the 

 terrible mortality of hospital nurses be diminished, if 

 not abolished ; the wards where they are occupied being 

 rendered as salubrious as those surgical wards in which 

 no bacilli could be found. 



Reflecting on the two investigations which I have 

 here endeavoured to bring, lucidly if briefly, before 

 my readers, the question arises ' What, under the 



