THE PROBLEMS OF GRADUATE MEDICAL INSTRUCTION
Journal of the American Medical Association
cases in which I have followed the above technic implicitly, the results have usually been better than anticipated. I am still looking for one of the nonspore bearing pathogenic bacteria which will stand 0.25 per cent, tricresol for twenty-four hours at 37 C. with¬ out losing its powers of reproduction. I have not experimented with the fungi, but am now experiment¬ ing with the tubercle bacillus along these lines. An unheated tuberculin similarly prepared may possibly give the same good
... e same good immunizing results obtained by the use of living virulent tubercle bacilli by Trudeau, Neufield, Webb, Williams and Barber, Theobald Smith and others. The above amounts of members of the phenol group do not interfere with such a delicate immunity reaction as complement fixation and probably have little or no influence on such reactions in vivo. This method of removal of vegetative powers might also be applied to sensitized vaccines; CONCLUSION Vaccines should not be heated above 37 C. but their vegetative powers should be destroyed by some method which does not change their immunity reactions from those of living bacteria. A method which is appar¬ ently successful with most micro-organisms is the use for this purpose of 0.25 per cent, tricresol solution for twenty-four hours at 37 C. Probably any mem¬ ber of the phenol group in the same bactericidal con¬ centration would be satisfactory.