184 MR. W. THOMSON ON THE CONSTRUCTION OF 



whilst the one inside was absolutely free from it, and it re- 

 mained free for nearly a month, when one little speck was 

 observed on it, which soon developed into a little button of 

 fungus. This showed that for three weeks after the paste 

 was placed in the room no spore had fallen on it. The 

 only cause of failure I could see was the glass, upon which 

 some spores must have adhered; consequently I had a 

 bag (C) made and sewn on above the Avindow, into which the 

 glass could be pulled in opening the window. When this 

 was done, the house was again crushed up and boiled in 

 water, again placed in position, the paste boiled, the window 

 closed ; and in this third trial the experiment was per- 

 fect. No fungus was developed on the paste inside the 

 house ; and after some months it dried up to a hard mass. 

 Thus these thin sheets of cotton wool forming a room of 

 10,032 cubic inches capacity, ^. e. capable of holding 36 

 gallons of air, were sufficient to prevent the entrance of 

 spores into it, and thus to preserve the flour paste from 

 decomposition during several months, till it had completely 

 dried up. 



These results, I think, conclusively show that ordinary 

 large rooms may be constructed, and ventilated with filtered 

 air by means of fans, so that flour paste, taken as a test 

 standard, would remain in them free from fungus-life ; and 

 I believe that such a room or series of rooms might be of 

 great advantage in surgery — perhaps as a means of pre- 

 venting spores from entering the wounds of patients, 

 and so doing away with or lessening the onus put upon 

 the antiseptic treatment, or in giving a better chance of 

 success in serious surgical operations. It is believed 

 by many medical men that pus and blood-poisoning may 

 be generated in a wound from the blood-corpuscles or bio- 

 plasts in the body, and that such developments have 

 nothing to do with the germs of the outside air, and that 



