178 SEVENTH REPORT. 



P. Russell of the University of Maine. Their method, which might be 

 designated as the "'potassium permanganate process," consists of pour- 

 ing a definite quantit}^ of formalin upon a fixed amount of potassium 

 permanganate. On adding formaldehyde to the K Mn O^ a rapid process 

 of oxidization ensues, and at ordinary room temperature the oxidization 

 causes profuse boiling, which liberates the formaldehyde gas very 

 rapidl3^ 



This method has the advantages that the disinfector need not trans- 

 jjort apparatus from place to place, that there is no generator or lamp 

 which might originate fire, that almost the whole quantity of formalde- 

 hyde available for disinfection is liberated very rapidly, thus giving a 

 maximum concentration of the gas before there has been time for leak- 

 age of the first part. But this latter advantage is only to be considered 

 when we are disinfecting organisms of low resistance. We know that 

 most of the organisms of contagious and infectious diseases have con- 

 siderable resistance, so this apparant advantage is scarcely worth con- 

 sidering. Inasmuch as the boiling process is of exceedingly short dura- 

 tion scarcely any steam is given ofl'. This lack of steam or moisture is 

 to be considered as a marked disadvantage in using the ''KMnO^ process," 

 and this is quite evident when a comparative study of the usefulness of 

 this method and that of distillation is made. 



The results of a long series of experiments led Dr. Evans to adopt 

 the proportion of 10 cc. of formalin to 3.75 grms. KMnO^ or approxi- 

 mately 6.5 ounces of KMn04 to one quart of formalin. In carrying out 

 this process of disinfection the commercial 40% formalin solution is 

 used, and it is most desirable for the permanganate to be either in the 

 powdered form or in the long needle shaped crystals which are met with 

 as the commercial article. 



If the large C. P. octohedral crystals are used they should first be 

 powdered so as to hasten the chemical reaction. As regards the gen- 

 erator an earthen or tin vessel with sides high enough to jirevent the 

 solution from boiling over will answer the purpose. 



In a room requiring 1000 cc. of formaldehyde, used in the proportion 

 of one quart to 1000 cubic ft. it is advisable to use a 3 gallon vessel. 

 He states that it is an advantage to use a generator with flaring sides, 

 so that the gas instead of ascending straight to the ceiling will ascend 

 forming an inverted cone, and consequently be diifused more rapidly 

 throughout the room. 



Dr. Evans quantitative experiments show that about 81% of the 

 formaldehyde was available for disinfecting purposes; the remaining 

 19% represents that part which has undergone oxidization. 



In view of the fact that the secretary of the Maine State Board of 

 Health makes strong claims for this procedure, Dr. Vaughan thought 

 it was desirable to have a. series of experiments made to prove or dis- 

 jjrove its usefullness. This investigation consisted of seven difl'erent 

 room-disinfection experiments. For two of the experiments the "perman- 

 ganate process" was used, and for the remaining five the formaldehyde 

 was distilled into the room by the Novy generator. 



Over 3000 specimens were exposed to the action of the disinfectant 

 in the two methods. The test organisms used were Diphtheria B. 

 Anthrax B. Subtilis, Typhoid B., Colon B., Cholera, S. Pyogenes Alb.. 

 Pyocyaneous, Pneumonia B., Streptococcus. 



