358 APPLIED B ACTEEIOLOGY 



certain number of organisms, varying in different cases, are 

 required to produce a toxic dose — that is to say, to make 

 headway as invaders against the healthy tissues ; the 

 number of organisms thus required doubtless varies with 

 the age and condition of the subject, the state of the 

 tissues, and the condition of virulence or attenuation of 

 the organism, while hereditary tendencies and other in- 

 fluences must not be neglected. 



It is in many cases advisable to attend to careful disinfec- 

 tion of the body of the patient — for example, in the case of 

 small-pox, measles, scarlet fever — while after diphtheria the 

 throat should be disinfected by means of a suitable gargle 

 till the Klebs-Loffler bacillus can no longer be found on 

 inoculation of serum-tubes. For disinfecting the skin or 

 the hands previous to an operation, a solution of mercuric 

 chloride (1 in 1,000) is convenient, the skin having been 

 well cleaned with soap and water, ether, turpentine, or 

 other suitable grease solvent. 



Clothes,' hangings, and bed-linen from infectious cases 

 should, if possible, be sent to a steam-disinfector, as they 

 are in no way injured by the process, and with an efficient 

 disinfector are rendered perfectly sterile. 



Excreta should be received into a 5 per cent, solution of 

 carbolic acid made in a saturated (24 per cent.) solution of 

 salt. If solutions of permanganates are employed, they 

 will certainly part with their oxygen to oxidisable organic 

 matter before the organised and resistant cell of the 

 bacterium is attacked. The ' disinfection ' of closets, 

 except in cases where they are used to receive excreta 

 from infectious cases, is neither necessary nor advisable; 

 in a properly-managed closet there is nothing to disinfect, 

 and the use of any agent to mask or destroy effluvia will 

 only lead to obscuring the ready perception of the in- 

 leakage of sewer gas, or the necessity of proper ventilation. 



