GEORGE F. REDDISH 307 



1. Sputum 50 per cent, disinfectant present in 1-50 



2. Sputum 50 per cent, disinfectant present in i-ioo 



3. Sputum 50 per cent, disinfectant present in 1-200 



4. Sputum 50 per cent, disinfectant present in 1-400 



The mixtures are thoroughly shaken at frequent intervals, and at the end of 30 minutes 

 each disinfectant mixture is injected in 2-cc. amounts into the right inguinal region of each of 

 two guinea pigs. With frequent shaking in the following interim, two more pairs of guinea 

 pigs are injected similarly at the end of an hour. Each pig in the first group receives 0.04 cc. 

 of disinfectant, in the second group 0.02 cc, in the third group o.oi cc, and in the fourth 

 group 0.005 cc. of disinfectant. 



Four control pairs of guinea pigs are then inoculated with 2-cc. amounts in like manner 

 with pooled sputum alone in the following dilutions: i-i, i-io, i-ioo, and 1-1,000. After 64 

 days all surviving animals are chloroformed and necropsied. The results given are based on 

 gross pathological changes only. Histological examination in every case might give positive 

 results in some of the cases reported as negative. It should be pointed out that in this experi- 

 ment the sputum and disinfectant were very intimately mixed, in a manner which cannot be 

 approximated in the ordinary use of disinfectants. 



PNEUMOCOCCUS AND HEMOLYTIC STREPTOCOCCI 



The pneumococcus Type II and hemolytic streptococci may be handled similarly 

 when used as test organisms in examining disinfectants. They require about the same 

 conditions for optimum growths, and the same technique and culture media may be 

 used for both. The technique used for these two organisms is briefly as follows: 



If the strain is from a blood-agar plate culture from fresh pathological material, transfer 

 from an isolated colony into lo-cc glucose broth of the following compositions: i per cent 

 Armour's peptone, 0.5 Liebig's beef extract, 0.5 per cent sodium chloride dissolved in dis- 

 tilled water and to which i per cent glucose is added; the final reaction after sterilization 

 must be between pH 7.2 and 7.4. Incubate at 37° C. for 24 hours, and then transfer o.i cc. 

 of the culture to 10 cc. of plain broth of the foregoing composition without glucose, but with 

 the same reaction, pH 7.2-7.4. Incubate at 37° C. for 24 hours and then transfer with a 4-mm. 

 platinum loop into another similar tube of plain broth and then carry out the test as outlined 

 for B. typhosus, using glucose broth for subculture medium. The subcultures in glucose 

 broth are incubated at 37° C. for 48 hours. Comparisons between the killing strength of the 

 disinfectant being examined may be made with phenol in the usual manner and the results 

 indicated as the "hemolytic streptococcus phenol coefficient" and the "pneumococcus phenol 

 coefficient." Two phenol controls are included in each test. The hemolytic streptococcus 

 should not be killed by 1-90 in 5 minutes, nor by i-iio in 15 minutes, while the penumococ- 

 cus should not be killed by i-ioo phenol in 5 minutes nor by 1-120 in 15 minutes. Results 

 with streptococcus strains especially indicate that a somewhat more concentrated dilution 

 of phenol might be selected, but in order that the limits may not be too exacting, the more 

 dilute solutions are suggested. It is certain that if cultures are killed by the dilutions of phe- 

 nol here given, they wiU not be acceptable as test organisms. 



ANTISEPTICS 



Antiseptics are substances which, when applied to micro-organisms, will render 

 them innocuous, either by actually killing the organisms or by preventing their growth, 

 according to the character of the preparation and the method of application.' For 



'Reddish, George F.: Drug Markets, 20, 495. 1927; /. Am. Phar. Assoc, 16, 501. 1927. 



