Questions regarding soil of House foundations, Streets and Alleys in Plague district.
1. Should the surface and sub-soil be removed, and to what depth?
2. Do you think it dangerous to move the sub-soil?
3. Would it, in your opinion, be likely to cause another outbreak of Plague?
4. Would it be dangerous to those assisting in the removal?
5. If you think So, do you think the danger could be obviated by continual application of disinfectants during removal?
6. Should the surface soil be entirely removed, and to what depth, and should it be destroyed, say by being sunk out at sea?
7. Will you examine some of the surface and sub-soil from infected houses to ascertain if bacteria can be found?
Sir,
HONGKONG, July 19th, 1894.
I have the honour to reply herewith to the questions you have submitted to me:-
1. The soil, floors, &c., can be removed without any danger, but care has to be taken that furniture, dust, the floors, the soil, &c., are never handled when dry. They have to be disinfected before with quicklime water and to be kept perfectly moist for one or two days, only after this time the things can be carried away. The depth of the soil which has to be removed depends upon how deep it has been infected, generally one third of a meter will be sufficient.
2 and 3. If it is done with the precautions given above, there is no danger to be expected.
4. The workmen are not in danger, but they ought to be warned to be very careful not to wound themselves, as in the soil of Hongkong are so many bacilli and spores of Tetanus that infection with Tetanus may easily occur.
5. In performing this work it is not necessary to supply each workman with a disinfectant.
6. About the depth vide No. 1. The removed soil can be safely thrown into the sea.
7. I examined several times the dust of the floors and the soil of infected houses about their bacteriological contents, and only one time I found in the dust of a house the plague bacilli. In soil taken from a considerable depth it has not been found so far. But those experiments have to be carried further on.
Allow me to remark that if the infected dwellings are to be thoroughly purified and freed from any plague germs a radical treatment ought to be enforced, the best is to burn completely at least the inner parts of the houses.
I have the honour to be,
Sir,
Your obedient servant,
(Signed) Prof. S. KITASATO.
To
(Translation.)
739
HONGKONG, 25th July, 1894.
MONSIEUR THE COLONIAL SURGEON,
I will endeavour, to-day, to reply to the questions which you addressed to me in your letter of the 17th July.
The first to resolve was to determine if the bacillus of the plague existed or not in the soil of the infected houses?
I have already made a microbiological analysis of the soil of a certain number of houses in which there have been cases of plague, both in Tai-ping-shan and other quarters of the town.
I have already observed that the microbiological analysis of the soil is a very delicate operation, and it must not always be concluded, from the absence of the sought-for microbe, that the result has been negative.
Such has not here been the case, and I have had no difficulty in discovering, in the soil of several infected houses, a little bacillus, identical, with regard to aspect and culture, to the plague bacillus. The microbe, inoculated into animals, does not kill the cobaye* or the mouse, it possesses no virulence. This property does not surprise me, for, already for a long time, I had begun to separate microbes of different virulence in the bubos; and have authentic cultivations of plague, which kill neither the cobaye* or the mouse, like the bacillus I have found in the soil.
To what depth can the microbe penetrate in the soil?
It is impossible to give you a precise answer to this question. In one house, where I examined the soil to the depth of 2 foot 6 inches, I did not find the bacillus, but that does not prove that there are none, there might be a very few.
Otherwise the penetration of the microbe in the depth of the soil depends above all upon the permeability and the greater or lesser humidity of the same.
Would it be dangerous to stir the soil?
At present, I do not think so, because, as I have already said, the microbe is no longer virulent. It is possible that, in order to renew its virulence, it might have to make a long evolution in the earth; but this is only a hypothesis, which would have to be supported by experience.
Would it be an advantage to move the soil to throw it into the sea?
Yes, if you could be certain to remove all the germs; but, who is to say whether all the soil of Hongkong is infected or not?
The rats tainted with the plague did not die only in the houses, but everywhere around.
This, Monsieur the Colonial Surgeon, is all that it is possible to answer you. I thank you for having furnished me with the opportunity of studying this interesting question of the presence of the bacillus in the soil.
SIR,
I beg you will accept the assurance of my respectful consideration.
DR. YERSIN.
COMMITTEE ON HOUSING THE CHINESE, HONGKONG, 28th July, 1894.
The Housing Committee has now the honour to lay before you, for the information of His Excellency the Governor, its views as regards the sanitary improvement of existing houses.
To Dr. P. B. C. AYRES,
Colonial Surgeon.
* 7 Guinea-pig.
Questions regarding soil of House foundations, Streets and Alleys
in Plague district.
1. Should the surface and sub-soil be removed, and to what depth?
2. Do you think it dangerous to move the sub-soil?
3. Would it, in your opinion, be likely to cause another outbreak of Plague?
4. Would it be dangerous to those assisting in the removal?
5. If you think So, do you think the danger could be obviated by continual application of disinfectants during removal?
6. Should the surface soil be entirely removed, and to what depth, and should it be destroyed, say by being sunk out at sea?
7. Will you examine some of the surface and sub-soil from infected houses to ascertain if bacteria can be found?
Sir,
me:-
HONGKONG, July 19th, 1894.
I have the honour to reply herewith to the questions you have submitted to
1. The soil, floors, &c., can be removed without any danger, but care has to be taken that furniture, dust, the floors, the soil, &c., are never handled when dry. They have to be disinfected before with quicklime water and to be kept perfectly moist for one or two days, only after this time the things can be carried away. The depth of the soil which has to be removed depends upon how deep it has been infected, generally one third of a meter will be sufficient.
2 and 3. If it is done with the precautions given above, there is no danger to be expected.
Tetanus
4. The workmen are not in danger, but they ought to be warned to be very careful not to wound themselves, as in the soil of Hongkong are so many bacilli and spores of such that infection with Tetanus may easily occur.
5. In performing this work it is not necessary to supply each workman with a disinfectant.
6. About the depth vide No. 1. The removed soil can be safely thrown into
the sea.
7. I examined several times the dust of the floors and the soil of infected houses about their bacteriological contents, and only one time I found in the dust of a house the plague bacilli. In soil taken from a considerable depth it has not been found so far. But those experiments have to be carried further on.
Allow me to remark that if the infected dwellings are to be thoroughly puri- fied and freed from any plague germs a radical treatment ought to be enforced, the best is to burn completely at least the inner parts of the houses.
I have the honour to be,
Sir,
Your obedient servant,
(Signed) Prof. S. KITASATO.
To
(Translation.)
739
HONGKONG, 25th July, 1894.
MONSIEUR THE COLONIAL SURGEON,
me in
I will endeavour, to-day, to reply to the questions which you addressed to
your letter of the 17th July.
The first to resolve was to determine if the bacillus of the plague existed or not in the soil of the infected houses?
I have already made a microbiological analysis of the soil of a certain number of houses in which there have been cases of plague, both in Tai-ping-shan and other quarters of the town.
I have already observed that the microbiological analysis of the soil is a very delicate operation, and it must not always be concluded, from the absence of the sought-for microbe, that the result has been negative.
Such has not here been the case, and I have had no difficulty in discovering, in the soil of several infected houses, a little bacillus, identical, with regard to aspect and culture, to the plague bacillus. The microbe, inoculated into animals, does not kill the cobaye* or the mouse, it possesses no virulence. This property does not surprise me, for, already for a long time, I had begun to separate microbes of different virulence in the bubos; and have authentic cultivations of plague, which kill neither the cobaye* or the mouse, like the bacillus I have found in the soil.
To what depth can the microbe penetrate in the soil?
It is impossible to give you a precise answer to this question. In one house, where I examined the soil to the depth of 2 foot 6 inches, I did not find the bacillus, but that does not prove that there are none, there might be a very few.
Otherwise the penetration of the microbe in the depth of the soil depends above all upon the permeability and the greater or lesser humidity of the same.
Would it be dangerous to stir the soil ?
At present, I do not think so, because, as I have already said, the microbe is no longer virulent. It is possible that, in order to renew its virulence, it might have to make a long evolution in the earth; but this is only a hypothesis, which would have to be supported by experience.
Would it be an advantage to move the soil to throw it into the sea?
Yes, if you could be certain to remove all the germs; but, who is to say whether all the soil of Hongkong is infected or not?
The rats tainted with the plague did not die only in the houses, but every. where around.
This, Monsieur the Colonial Surgeon, is all that it is possible to answer you. I thank you for having furnished me with the opportunity of studying this interesting question of the presence of the bacillus in the soil.
SIR,
I beg you will accept the assurance of my respectful consideration.
DR. YERSIN.
COMMITTEE ON HOUSING THE CHINESE, HONGKONG, 28th July, 1894.
The Housing Committee has now the honour to lay before you, for the infor- mation of His Excellency the Governor, its views as regards the sanitary improve- ment of existing houses.
To Dr. P. B. C. AYRES,
Colonial Surgeon.
* 7 Guinea-pig.
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