248 president's address — section i. 



ing air and rapidly cooled, so that it will remain below the head level 

 of other persons. There is, therefore, reason to believe that the risk 

 of infection is less than would at first sight appear. Indeed, the matter 

 resolves itself into a question of the ventilation of the workroom, which, 

 if sufficient, will bring about the dilution and removal of the com- 

 paratively small quantity of infectious exhalation. Fliigge is probably 

 right when he says that a metre is a safe distance from the worker who 

 may be seated or standing in a workroom, always provided that the 

 room is sufficiently ventilated. One point, however, arises which may 

 influence the safety of workers who are seated even at some distance 

 facing a consumptive. There is the possibility that in coughing, a 

 vortex-ring may be sent out which will carry the spray particles straight 

 across the intervening space to the face of a susceptible fellow-worker 

 who may breathe a portion of the ring. If such vortex-rings are given 

 out, and I think it probable that they are, a known consumptive should 

 be caused to stand or sit behind a network screen of some kind, or facing 

 a wall. 



Much has been written about the infectivity of consumptive 

 sputum, but a consideration of the subject shows that the danger has 

 been exaggerated. When thrown upon the ground it falls as a mucinous 

 paste, which dries to a stiff mass. This breaks up after the lapse of a 

 considerable time into comparatively large particles, which are not 

 easily transported. The conditions that obtain with naturally-dried 

 sputum are quite different from those that occur in experimental 

 infections, in which the sputum is dried quickly, broken up by mechani- 

 cal means, and distributed by strong air currents. This aspect of the 

 case has been noted by Fliigge, and more recently by Cadeac (32), who 

 further emphasised the fact that the exposure to light and air, during 

 the time that must elapse before it becomes broken up, weakens the 

 bacilli to such an extent that they are unable to set up tuberculosis 

 in the extremely sensitive guinea-pig otherwise than with the greatest 

 difficulty. And he argues that if the intracorporeal infection of the 

 guinea-pig is so difficult, it will be well-nigh impossible to infect the 

 air-passages of man. There is, therefore, reason to believe that tuber- 

 culous sputum, when thrown upon the ground, is not actually dangerous ; 

 and such being the case, the chief means of infection, outside of the 

 food supply, is the consumptive cough. 



Just as we should rigorously examine the cows which supply milk 

 for the child and the invalid, so should we keep under observation the 

 consumptive, who is a source of danger to the adult population ; and, 

 although this is beyond the scope of my address, yet I feel that I ought 

 to express the conviction that drastic measures of any kind will not 

 be tolerated by the community, and that the only means that are 

 open to us in these days of enlightenment is to insist upon compulsory 

 notification, and to have tactful State and municipal officials as public 

 educators who will be advised by the medical attendant as how best 

 to approach the patient, in order to explain the danger to which he or 

 she may expose innocent individuals. 



