1908] 0)1 The Present Phase of the Tubercidosis Prollem. 289 



Tuberculous persons emitting bacilli in their sputum were placed 

 in a glass chamber, in various parts of which were deposited suitable 

 culture plates, and after periods of coughing on the part of the 

 patients, the plates were collected, and when incubated, carefully 

 examined ; a large number of the plates placed both in front of and 

 behind the patient were found to show growths of tubercle bacilli.* 



With the dust school, the collection and destruction of sputum are 

 alone necessary to ensure safety from infection ; with the droplet 

 school, safety is to be ensured by holding a handkerchief before 

 the mouth and nose during periods of coughing, sneezing, and excited 

 speech. This droplet school points to certain experiments with 

 sputum which indicate that before sputum can, as a rule, reach the 

 dust phase, the bacilli which it contains are dead or dying, and it is 

 urged that bacilli freshly given off from the host in which they have 

 thriven are more likely to possess potency for harm than those which 

 have left their natural habitat many days. 



Both schools believe that infection is brought about by inhalation, 

 whether of droplets or of dust, into the lungs. 



Channels of Infection. 



Even as there are two sharply divided schools of thought re- 

 lative to the vehicles of infection, so also are there two schools as to 

 the channels by which the tubercle bacilli gain access to the body. 



One school believes that the bacilli, wet or dry, stale or fresh, 

 enter the body via the lungs ; the other school holds that the para- 

 sites enter the body by way of the alimentary tract. There is experi- 

 mental evidence in support of both these views. 



For the most part each school believes that the bacilli, however 

 taken in, set up definite disease within a short space of time, and, in 

 so far as this belief obtains, both schools may be spoken of as schools 

 of immediate infection. 



Without expressing opinion as to which of these routes is the 

 more important, it may be said that recent work carried out in this 

 and other countries is in support of the view that the intestine is 



* Some idea of the manner in which bacteria, given off from droplets of 

 saliva, may be wafted about by the air may be gath.ered from the experiments 

 by Gordon in our own House of Commons. Having exposed culture plates in 

 all parts of the House — in the galleries as well as in the Chamber itself — he 

 was able to ascertain that the air of the House contained, as a rule, none of 

 the bacilli {B. prodigiosus) which he proposed to employ in the experiment. 

 He then exposed fresh culture plates, and occupying the position of the Prime 

 Minister, and washing out his mouth from time to time with a solution of the 

 bacilli in question, he proceeded to address various sections of the House by 

 reciting long passages from Shakespeare — Julius Caesar being selected as afford- 

 ing suitable opportunities for declamation. It was found upon collecting and 

 incubating the plates that some in practically every part of the House had 

 become inoculated. 



YOL. XIX. (No. 102) U 



