S. p. KRAMER 



563 



the basic filter. The base, morphia, does not exist in opium, but is an artefact — the 

 product of chemical manipulation. 



Thirty gm. of powdered cocoa leaves were extracted with 200 cc. of 50 per cent 

 alcohol for twenty-four hours. Of the extract, 100 cc. were evaporated in a water bath 

 to 30 cc. When injected into a 25-gm. mouse, i cc. of the extract paralyzes the respi- 

 ration and kills the mouse within one hour. When filtered through the gypsum - 

 magnesia filter, the filtrate is non-toxic. The alkaloid cocaine is not removed by the 

 same filter, but is taken out by filtration through the Berkefeld colloidal silica filter. 



An infusion of powdered nux vomica, i part in 20 parts of water, was found to be 

 fatal to mice in six minutes, producing typical strychnine convulsions. The filtrate 

 from the gypsum-magnesia filter was equally toxic. The silica gel-Berkefeld filtrate 

 was non-toxic and tasteless. Powdered calabar bean was extracted with 10 volumes of 



TABLE I 



alcohol, the fluid placed in a water bath and the alcohol driven ofi". Water was then 

 added up to the original volume. One cc. of this water extract was fatal to mice within 

 five minutes, causing violent tremors and paralysis. The gypsum filtrate was equally 

 toxic. The silica gel-Berkefeld filtrate was non-toxic. The same result was obtained 

 with an infusion of tobacco, i part in 10 parts of water, the gypsum filtrate being 

 toxic, the silica gel-Berkefeld filtrate being non-toxic. 



In Table I, I have arranged the various substances experimented with and their 

 reactions as found by differential filtration. 



It would appear that of those neurotoxic poisons which are removable by filtration 

 those which are positively charged or "acidophilic" are predominately spinal in their 

 action; while those which are negatively charged or "basophihc" are predominately 

 extra-spinal in their action. 



If a dry Berkefeld filter be thoroughly saturated with paraffin oil as suggested by 

 Holman,' it will lose its power of separating out colloid dyes. Both the acidic and 

 basic dyes will pass through. The same thing is true of the gypsum filter provided 

 care is taken that the filter is perfectly dry before saturation with the paraffin oil. In 



' Ilolman, W. L.: Am. J. Path., 2, No. 5, 4S3. 1926. 



