106 THE AMERICAN MONTHLY [Apr., 



at a much earlier period than in cases not so treated — a 

 fact of importance in determining the limits of the period 

 of quarantine — and clinicians have shown that the mor- 

 tality and duration of the disease have been favorably 

 influenced by such treatment when commenced early and 

 efficiently carried out. We are all familiar with the ex- 

 cellent results reported to us in this disease by the use 

 of sprays of bichloride of mercury by our friend Dr. 

 Robert Reyburn. 



Bichloride is, however, a dangerously poisonous drug 

 and moreover has the disadvantage of forming with al- 

 buminous materials an insoluble albuminate which would 

 seem to limit its action to the more superficial layers of 

 the false membrane, unless used in excessive quantity, 

 while other commonly employed germicides are open to 

 the objection that they cannot always be used in suflic- 

 ient amount and concentration to be positively destruc- 

 tive to the bacilli without injury to the healthy tissues 

 or harm to the system generally. Upon reading Mr. 

 Schering's claims for formalin to the efl'ect that this 

 agent is as potent as bichloride as a germicide without 

 being so toxic and acts equally well in albuminous as in 

 non-albuminous media it at once suggested itself to my 

 mind as a valuable agent in cases of diphtheria and I ac- 

 cordingly set about testing its effects upon the diphthe- 

 ria bacillus. 



I first covered the bottoms of some Petri (double) dishes 

 to the depth of from 1-16 to i of an inch with glycerine 

 agar, inoculated them with the diphtheria bacillus by 

 drawing a platinum needle, dipped in a recent pure cul- 

 ture, several times across the agar carrying the needle to 

 the bottom of the plate. I now lightly sprayed the sur- 

 face with formalin varying in strength from a 10 per cent 

 solution to 1 part in 1,000 and placed all the cultures so 

 treated together with two similar cultures without the 

 use of the formalin spray in the incubator. At the end 



