TETANUS TOXIN NEUTRALIZED BY BRAIN SUBSTANCE. 361 



METHOD OF MAKING THE EXPERIMENTS. 



The method employed followed exactly in principle that em- 

 ployed by Kitashima. A 1 to 400 dilution of the normal solution 

 of the poison was prepared. To each cubic centimeter of this, which 

 represents forty times the fatal dose for a mouse of 15 grm., the 

 desired number of doses of brain emulsion, or of a 1: 10 dilution of 

 this emulsion was added, the fluid made up to 2.5 cc. by the addition 

 of 0.85% NaCl solution, and the mixture thoroughly shaken. At 

 the end of an hour 0.5 cc. of the dilutions of serum in question were 

 added and after once more thoroughly shaking, -J-cc. doses of this 

 mixture were injected subcutaneously into white mice weighing 15 grm. 

 It may be mentioned that in the controls containing only brain and 

 poison the procedure was exactly the same except that 0.5 cc. NaCl 

 solution were added at the end of the hour instead of 0.5 cc. serum. 

 The control containing only poison and serum was treated in exactly 

 the same manner and was injected in the usual way after the anti- 

 toxin had been allowed to act in the toxin for thirty minutes. It 

 may be added that no appreciable difference was observed if the 

 mixture of poison +brain+ serum was injected directly after the 

 addition of the serum or if the serum was allowed to act on the brain 

 + poison mixture for half an hour. 



RESULTS OF THE EXPERIMENTS. 



My results, obtained from over two hundred experiments on 

 mice, do not furnish the slightest ground for assuming that the phe- 

 nomenon found by Kitashima is the rule. On the contrary, from 

 my experiments I can positively conclude that there is always a 

 summation of the poison-neutralizing action of the brain and anti- 

 toxin; furthermore that there is never any 'interference with the 

 antitoxic action of the serum as a result of the previous action of 

 the brain on the tetanus poison. This fact was constantly observed, 

 no matter whether large or very small doses were employed. The 

 series of tests with brain emulsions, as well as those with brain and 

 poison alone without serum, do not, to be sure, proceed as smoothly 

 as those with poison + serum ; however, this is not at all surprising; 

 on the contrary, it is quite natural that the particles suspended in 

 the emulsion, even if they are very fine, cannot produce as uniform 

 effects as a solution of antitoxin. 



