chap.v PLAGUE IN THE EAT 85 



whether the numbers I have given of ships that have 

 had plague among rats on board them should not be 

 materially reduced " — that is to say, the instances in 

 which the diagnosis relied only on microscopic examina- 

 tion, and was not supplemented by culture and animal 

 experiment. 



Dr. Thomson, in respect of danger (1) takes (pp. 318- 

 319) "the four years 1898-1901, and finds that in 95 

 ships plague appeared, whether in rat or man ; on 

 58 of these vessels plague was observed in man only ; 

 on 28 it was observed in both rats and man ; while on 

 9 it was observed in rats only." 



We quote here some of the passages of Dr. Thomson's 

 Eeport, p. 319 and passim : — 



"In all, therefore, plague among rats was observed on 37 ships 

 during the four years in question. As regards the 28, out of these 

 37, on which both man and rats were affected, it may, in some cases 

 at least, be questioned whether the primary source of infection from 

 shore was the rat or the human subject. To this point reference 

 will be made later. Be this as it may, however, these data seem to 

 indicate that transference of infection from shore to ship is more 

 likely to occur through man than by the rat. Nor do they point to 

 a serious degree of danger of this sort, since only some nine vessels 

 per year are recorded as having developed plague among rats on board. 



In this connection, it is of interest to consider the number of 

 vessels leaving Bombay, a plague-infected port, for ports out of India, 

 during the period 1898-1901, on which plague, whether among rats 

 or men, is known to have made its appearance after departure from 

 Bombay. The measures taken at Bombay as regards these vessels 

 prior to their departure were medical examination, by day and on 

 shore, of every person proposing to sail by them ; disinfection of 

 clothing, bedding, and effects of native crew, third-class and deck 

 passengers ; attention to the sanitary condition of the vessels, 

 leading to such action as cleansing and disinfection of crew's 

 quarters, cleansing of bilges, and, in the case of ships in ballast, 

 the cleansing of 'tween decks and holds. 



