164 REVIEW — TBOPICAL MEDICINE, ETC. 



Plague— There is now not a shadow of a doubt that the rat is the cause of plague epidemics, and no evidence is required to 



continued convince most people, and especially the natives of this country, that the best way to get rid of rats is to keep 



cats. Even if isolation, disinfection and inoculation were of much value, they do not strike at the root of the 



disease. Rat destruction by traps and poison is troublesome and costly, though effective if the staff employed on 



this work is continuously energetic, but the cat requires no stimulus. 



That the cat is available, or can soon be made available in sufficient numbers in this district, is clear from 

 the census that has recently been taken, and from the fact that there is the greatest willingness on the part of the 

 people to obtain young cats and keep them. 



The strongest point in favour of the cat is — a fact which very few Europeans in this country know — that it is 

 almost a religious duty with a Mohammedan to keep a cat, and that Hindus consider it a groat sin to injure even 

 a single hair of a cat. It is now recognised that the success of measures for plague prevention depends very 

 greatly on the attitude of the people towards it. The strongest point in favour of recommending the keeping of 

 cats is that any prejudice that is likely to be met with is in favour of, and not against, the keeping of cats, 

 excepting in the case of the Bhowan Dliers and a few Jains (and their numbers are not large). It is clear then 

 that the cat is effective ; that it strikes at the root of the disease ; and in this district it is available, and 

 that it is acceptable to the people. During the past ten years I have seen many measures introduced for 

 plague prevention. To all there has been more or less opposition. To the keeping of cats there is practically 

 no opposition, and it is clear that the keeping of cats is j)ar excelleiice the people's remedy for plague prevention. 



An interesting suggestion is that made by SaigoP to the effect that rats and guinea pigs 

 should be used as "plague barometers." His argument is that if these rodents are kept in 

 the house, fleas leaving an infected dead rat will attack them in preference to human beings. 

 He suggests several cages to each household, each containing at least three rats. Guinea 

 pigs also attract P. cheopis. These animals v?ill then act: (1) As " plague barometers"; 

 (2) as flea-catchers and retainers — flea traps, in short ; (3) as " locality indicators." Saigol 

 notes that the method cannot be said to be unnecessary, because it is well known that on 

 the appearance of an epizootic amongst rats all the healthy ones quit the locality leaving 

 their sick and dying behind. These latter are the source of infection. " Barometer rats," 

 being unable to escape, would indicate the presence of the disease. 



The same author- has recently recorded his experiments with the Danysz virus, " ratin," 

 " azoa," " common sense exterminator," and sulphur fumigation. In no instance have the 

 results been entirely satisfactory, and, as regards rat destruction on a large scale, the 

 outlook is at present none too hopeful. 



Colvin^ has a paper on the latency of plague and its spread by means of fomites, citing 

 cases in connection with the Glasgow epidemic. There seems to be no doubt that in these 

 instances the infected clothing conveyed the contagion. He concludes with the following 

 quotation from Simpson's well-known treatise on plague : — 



There is one feature of the present pandemic of plague that presages danger in the future. It is that 

 notwithstanding its apparent inability to cause in one place a great epidemic, it exhibits in some places 

 marvellous powers of recrudescence and resistance to all kno^vn measures of prevention, and this even when the 

 cases are few. This tenacious capacity, combined with its transportability, makes it formidable because its 

 slow progress, few cases, and possibly slight mortality accustom the people to its presence and lull the authorities 

 into a frame of mind of looking upon it as a disease that can be easily controlled. In the meantime it gradually 

 dots itself over different parts of the country, securing a firm hold in some localities, which again form fresh 

 centres for its activity, until in the course of a few years it is firmly established in the country at many centres 

 and only awaits the conditions necessary for its development into an alarming epidemic. 



Thompson'' deals with experiences in Sydney, and is of opinion that the exclusion of 

 rats from occupied buildings in cities is the only measure which can permanently diminish 

 the susceptibility of India to plague. This, as he points out, is the true preventive 

 method, the use of the prophylactic, evacuation of infected places, and rat destruction being 

 remedial. 



Something has already been said regarding the disinfection of ships infected with plague 

 and infested with rats [see " Disinfection," page 44), but a note on a paper by Bonjean* 

 may be quoted : — 



In 190.3 the International Conference, meeting at Paris, indicated three processes : (1) an admixture of 

 sulphurous acid with a small quantity of sulphuric acid ; (2) a mixture of the monoxide and dioxide of carbon ; 

 and (3) carbon dioxide. Of these methods the first is destructive to insects and bacteria as well as to the rodents. 

 At Hamburg the toxic gas consists of carbon monoxide, 5 volumes ; carbon dioxide, 28 volumes ; and nitrogen, 



1 Saigol, R. O. (December, 1907), "Rats and Guinea Pigs as 'Plague Barometers ' d. Rat Destruction." 

 Indian Medical Gazette, Vol. XLII. 



- Saigol, R. 0. (July, 1908), "Rat Extermination." Indian Medical Gazette. 



' Colvin, T. (November 30th, 1907), " Is Bubonic Plague stUl lurking in the City of Glasgow?" Lancet, 

 Vol. II. 



♦ Thompson, J. A. (December 21st, 1907), " Protection of India from Invasion by Plague." British Medical 

 Journal, Vol. II. 



* Bonjean, E. (March 21st, 1908), " Means Employed for the Destruction of Rats on Ships." Lancet, Vol. I. 



