316 FKAGMENTS OF SCIENCE. 



the body epidemic disease. If this be so, then disease can 

 be warded off by carefully-prepared filters of cotton-wool. 

 I should be most willing to test their efficacy in my own 

 person. But apart from all doubtful applications, it is per- 

 fectly certain that various noxious trades in England may 

 be rendered harmless by the use of such filters. I have 

 had conclusive evidence of this from people engaged in 

 such trades. A form of respirator devised by Mr. Garrick, 

 a hotel proprietor in Glasgow, in which inhalation and ex- 

 halation occur through two different valves, the one per- 

 mitting the air to enter through the cotton-wool, and the 

 other permitting the exit of the air direct into the atmos- 

 phere, is well adapted for this purpose. But other forms 

 might readily be devised. 



Fireman's Respirator. 



Smoke is often the fireman's greatest obstacle in his 

 efforts to save life ; I thought, therefore, of inventing a res- 

 pirator for the use of firemen. Schroeder was the first to 

 use cotton-wool as a filter. To catch the atmospheric 

 germs, M. Pouchet employed a film of adhesive glycerine 

 spread upon glass ; while Dr. Stenhouse turned charcoal to 

 important account in respirators. By a combination of all 

 three a respirator of peculiar efficacy is obtained. For the 

 smoke of dried leaves the cotton-wool alone was found an 

 adequate protection ; but for the far more pungent smoke 

 of resinous deal it was found totally inadequate. At the 

 suggestion of a friend I moistened the wool with glycerine, 

 and found it a great improvement. It was the notion of 

 Pouchet in another form. Still about five minutes in dense 

 smoke was all that could be endured. I then associated 

 fragments of charcoal with the moistened cotton ; the effect 

 was excellent. 1 Armed with a respirator of this kind, one 

 1 Mr. Ladd, of Beak Street, makes these respirators. 



