536 The Philippine Journal of Science 1923 



In as thin a film as possible. A diffuse growth resulted in the 

 inoculated agar tubes. 



The results shown in the attached tables were noted at given 

 intervals of time and were arrived at by comparing the growth 

 in the particular agar tube with that in the control tube. 

 Cultures showing growth scantier than that in the control tube 

 were considered as showing inhibition of growth and so marked 

 in the tables. 



It will be noticed that my figures indicating the titer of 

 various oils do not agree with those of Walker and Sweeney. 

 I prefer to give as a titer the quantity of the substance added 

 to the culture medium rather than to give the final dilution 

 of the drug in question, for the reason that it is impossible to 

 estimate the exact amount of drug which comes into action 

 when solid media are used and the culture is growing on the 

 surface only. It is reasonable to assume that a quantity smaller 

 than the one corresponding to the amount of the final dilution 

 comes into action at a time under such conditions. This cir- 

 cumstance may be considered a disadvantage ; on the other hand, 

 there is a fairly even distribution and, so to speak, fixation of 

 those drugs which in liquid media have the tendency to gather 

 either on the surface or at the bottom of the medication tubes, 

 or to precipitate out of solution. Moreover, the storage effect 

 comes into action under these circumstances. The drug stored 

 and preserved in the solid medium is less apt to undergo such 

 changes (hydrolysis) as take place rather rapidly in high 

 aqueous dilutions. The drug is given off from under the sur- 

 face in as concentrated a solution as its solubility in water 

 permits and is taken up by the growing cultures in as large 

 an amount as its solubility in water and fats allows. 



Furthermore, it was the purpose of these investigations to 

 ascertain the fundamental principles of the direct action of 

 various drugs on acid-fast bacteria rather than to set their 

 definite and constant antiseptic values or indices. For the 

 same reason, as will be noticed, the final dilutions in the culture 

 media, of the substances tested, were made at rather large and 

 irregular quantitative intervals. 



This experiment (Table 1) tends to show that chaulmoogra oil 

 has a considerable inhibiting power over B. tuberculosis and that 

 the growth-inhibiting action is specific; that is to say, the chaul- 

 moogra inhibits the growth of B. tuberculosis in high dilutions 

 while liquid paraffin and olive oil do not prevent the growth 

 of this microbe. Non-acid-fast bacteria are not inhibited by 



