APPENDIX. 



THE CONSTRUCTION OF STEAM-DISINFECTORS. 



The difference in efficiency between various steam-disin- 

 fectors depends not only on the general method of their 

 construction, but also on the proportions and details of 

 their design. In this appendix it is only possible to describe 

 the general construction of those steam-disinfectors which 

 are best known. 



Lyon's Disinfector. — This consists of a horizontal 

 chamber, either oval or circular in section, surrounded by 

 a jacket, and closed at either end by a door. Steam is 

 admitted through safety-valves to the jacket and to the 

 central chamber, in which the objects to be disinfected are 

 placed. The pressure usually employed is about 20 lb. in the 

 interior of the cylinder and about 25 lb. in the jacket, the 

 object being to slightly superheat the steam and diminish 

 the extent to which condensation takes place on the objects 

 to be disinfected. The present method of eliminating the 

 air is to apply a vacuum apparatus, whereby the air within 

 the disinfecting chamber is rarefied to 15 to 20 inches of 

 mercury — i.e., one half to two-thirds of the air is extracted 

 before steam is admitted. In some cases a current of 

 warm air is also admitted before disinfection, so as to 

 diminish the extent of condensation. The drying of objects 

 after disinfecting is effected by extracting some part of the 

 vapour by means of the vacuum, and allowing the re- 



