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Unfortunately the methods at our disposal for the destruction of rats are few, especially when applied to a generalised destruction of the species.
The various poisonous preparations in the market are of little value.
The Bacillus Dany sz has not so far justified the hopes at first entertained for it. Some observers as BRONSTEIN (Deut. Med. Woch. No. 34, 1901) and KISTER (Deut. Med. Woch. No. 18, 1901) have obtained good results on a small scale. On the other hand, such bacteriologists as KOLLE (Dent. Med. Woch. No. 4, 1902), ABEL (Deut. Med. Woch. No 99, 1901), KRANSZ (Deut. Med. Woch. No. 22, 1901) and others, have had uniformly bad results. My own results are in conformity with those of the latter workers. Recently Professor Roux of the Pasteur Institute in Paris has had wonderful results with his virus. I have put myself in communication with him in regard to his methods, which I hope to apply in Hongkong which is veritably rat infested.
Summary of Prophylaxis.
The foregoing principles of general and special prophylaxis have been stated in as concise terms as possible. The prophylactic measures against the intro- duction of the exotic into a sea port or inland town have been dealt with.
It only remains now to sketch as briefly as possible the measures which I consider neces- sary to deal with the disease after its introduction. These consist in the following:-
(1.) The absolute control of provinces supposed to be infected.
(2.) An early recognition of the disease, which is attained through:-
(a.) Compulsory post-mortem examinations.
(b) Immediate notification of all cases to the sanitary authorities.
(c.) Systematic search in infected areas and neighbourhood for other
cases of the disease and sources of infection.
(d.) The examination of rats.
(e.) The provision of opportunities for the study of the disease
from all points of view.
(3.) The isolation of infected persons if necessary.
(4.) The medical supervision of relations and contacts.
(5.) The provision of segregation camps.
(6.) Wholesale measures must be directed against rats and other verinin. (7.) The education of the people especially in regard to cleanliness, cook-
ing of food, boiling of water, etc.
(*) Skilled veterinarian supervision of all food supplies. (9.) The thorough disinfection of infected districts.
(10.) The thorough cleansing of non-infected districts.
In the above list protectire inoculation is not recommended. Such protective powers as are conferred on man by the inoculation of plague vaccine are transient. It is doubtful if the protection afforded lasts more than a few weeks.
Nor is the employment of plague serum advocated. Such sera contain only part of the complex molecular body requisite for complete bacteriolysis, hence the results obtained, Much more research is required in this direction before we find a specific serum for plague.
The
Again, the wholesale employment of disinfectants is not recommended. They are expensive and their beneficial action in general is doubtful. The e'n- ployment of disinfectants ought to be restricted to actual infected areas. promiscuous use of disinfectants as cleansing agents in districts not infected is to be discouraged. Much more, or at least as much good, accrues from the use of soap and a plentiful supply of water.
During the absence of epidemics of plague in man, our energies ought to be directed against the omnipresent rat plague. In the absence of primary pneumonic plague I am convinced that the eradication of plague from any country, district, city or town is subject to the complete extermination of rat plague.
WILLIAM HUNTER.