270 A MANUAL OF BACTERIOLOGY 



cases are those which it is of the greatest importance to 

 identify, especially in schools, for if not recognised the 

 patients may go about and prove a source of infection 

 to all around. The method also affords valuable evidence 

 as to when a case can be considered free from infection ; 

 so long as bacilli are present in the throat infection must 

 be possible, and the length of time for which they may 

 occasionally persist is remarkable. In half the cases the 

 bacilli disappear within three days of the disappearance 

 of the membrane, in a few cases they linger for as long 

 as three weeks, but occasionally they persist much longer. 

 The writer isolated them for so long as five months (and 

 virulent to the last) ; and a case is recorded in which they 

 persisted for no less than fifteen months after the attack. 

 In all cases two or three examinations should be made at 

 short intervals with negative results before the bacilli 

 can be pronounced to be absent, and no case should be 

 discharged from hospital until the absence of bacilli has 

 thus been proved. When bacilli persist, treatment with 

 antiseptic sprays or gargles, combined with syringing the 

 nose, may be tried. Syringing the nose is important, for 

 the bacilli probably extend to the post-nasal space, where 

 they are untouched by a throat spray or gargle. Another 

 mode of treatment has also been adopted. A polyvalent 

 anti-microbic agglutinating anti-diphtheria serum has been 

 prepared, dried, and compressed into tablets, one of which 

 is dissolved in the mouth every two hours, and fifteen 

 minutes after solution the naso-pharynx is flushed with 

 physiological salt solution. While this treatment some- 

 times succeeds, it often fails. The writer has tried the 

 use of subcutaneous inoculations of diphtheria endotoxin 

 (2-0-5-0 mgrm.) at intervals of seven to ten days. About 

 half the cases seem to clear after one to three injections. 



With regard to the value to be attached to the bacterio- 

 logical examination for diphtheria, while the finding of 



