12 qUatercentenary studies in pathology 



Of course, these indifferent results were obtained in the case of a 

 room which was by no means hermetically sealed, but it was in the 

 same condition as when the corresponding test was made with Lingner's 

 apparatus ; and it is well not to rely on any very careful sealing of 

 rooms in the large number of fumigations which have to be carried 

 through by sanitary officers in times of heavy epidemics. The better 

 results obtained by some other observers were no doubt largely due to 

 the more careful sealing of the rooms. 



3. — The Permanganate Process. 



This method is based on the fact that, by the mixture of formaline 

 and potassium permanganate, a copious liberation of gaseous formal- 

 dehyde takes place. 



The State Board of Maine recommends the following method : — In 

 the centre of the room is placed a large vessel containing the requisite 

 amount of potassium permanganate. The proper quantity of formaline 

 is then added. As much foaming occurs, it is well to place the vessel 

 within a large pan. 



For each looo cubic feet, 13 ounces of potassium permanganate and 

 2 pints of formaline are used. It may be mentioned that the New 

 Hampshire Board, who have also employed this method, considers that 

 smaller quantities of the substances (3J ounces of potassium perman- 

 ganate and I pint of formaline to the 1000 cubic feet) serve the purpose 

 equally well. 



Experiments were carried out by the Maine authorities on the 

 following micro-organisms : — B. diphtherias, B. typhosus, B. coli, B. 

 pyocyaneus, B. anthracis, B. subtilis. Staphylococcus albus, S. aureus, 

 Streptococcus pyogenes, &c. After an exposure of 3 hours to the action 

 of the disinfectant, out of 1529 test objects, only 27 showed any growth, 

 and of these, 21 were Bacillus subtilis. 



In these experiments the ordinary openings of the room were closed, 

 but in no case were precautions taken to close up cracks and crevices. 



The following is a description of my own experiments with these 

 methods : — 



Experiment i. 



This experiment was carried out in the same house as that used in 

 experiments with the two last-mentioned methods, and the same 



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