474 
forty-eight hours after the finding of the suspicious patient or of the 
dead body and during the examination the patient or the dead body is 
to be regarded as if it were a genuine instance of plague infection. 
Even during ordinary times, the killing of rats is enforced in localities 
where imported freight is stored or where laborers live and this enforce- 
ment is made general when there is danger of an outbreak of plague. 
At least two days before the general sanitary precautions outlined above 
are applied, rat catching and killing devices, such as traps and poisons 
are distributed to every dwelling and warehouse. Formalin vapor or 
sulphur dioxide is used in buildings which can be tightly closed. All 
localities which are constructed so as to permit of the abode of rats are 
rebuilt, the sewage is improved, and all filth is burned. The above 
constitute the measures employed for removing and killing rats. The 
occupants of the dwellings in which infected rats are frequently found, 
or in which plague patients are discovered, are removed and the whole 
house disinfected and rendered unfit for rodents by the sanitary meas- 
ures adopted in the killing of rats; in order more effectually to destroy 
the latter, galvanized-iron walls are erected around such houses and all 
exits of the sewers are closed by means of metal nets. If the infected 
area is extensive it is divided into small sections, and the same method 
is applied to each one of these. The first steps in sanitation after 
these precautions have been taken are to search for and destroy the 
rats, to disinfect the furniture and finally the entire building. For the 
latter purpose carbolic acid, corrosive sublimate and lime are used, 
articles of an especially suspicious nature being at times steamed, boiled, 
or burned; all of the disinfected objects are ultimately exposed to the — 
sunlight. In case the building is situated in such a manner as to render 
the application of sanitary measures difficult, it is sometimes desirable 
to disinfect by burning the entire edifice. Such extreme measures I 
believe to be especially justifiable where the infection has not as yet 
spread to a large area, and they are not infrequently made use of in 
Japan. The galvanized-iron fence or wall which is erected before fire 
is set to the premises prevents the rats from finding their way to the 
neighboring houses, and thus possibly spreading the disease. 
However, the difficulties attendant upon the entire destruction of 
houses for purposes of disinfection are in some instances insurmountable, 
and this is particularly the case when plague patients and infected rats 
are scattered over a large area. The present epidemic in Osaka and 
Kobe illustrates such a situation. If extreme measures were to be ap- 
plied to these cities practically whole districts would have to be burned. 
As has been remarked above, the zine fences prevent the escape of rats 
during the work of disinfection and their effectiveness in segregating 
an entire area before an epidemic becomes general has been abundantly 
illustrated during the outbreaks in Yokohama, Kobe, and Tokyo. These 
walls present a most peculiar appearance. (See Pls. X-XII.) Their 
