56 



SMELL, TASTE, ALLIED SENSES 



tion of 0.006 milligrams per liter of air which is equal 

 to 6/1,000,000 of a milligram per cubic centimeter. 

 This determination is by no means so extreme as that 

 of Fischer and Penzoldt, 1/23,000,000,000 of a milligram 

 per cubic centimeter. Whether this difference is due to a 

 difference in the compounds used, for Fischer and 



Table III. 

 Concentrations in Milligrams of Chemical per liter of air. 



Penzoldt do not state what mercaptan they tested, or 

 whether it represents a difference in the methods em- 

 ployed cannot be stated. In the table from the work of 

 Allison and Katz, as in all previous sets of determination, 

 artificial musk is shown to be without question the most 

 stimulating substance tested and thus stands at the head 

 of olfactory stimuli. 



Notwithstanding the numerous discrepancies between 

 the various sets of determinations for olfactory acuity 

 made by various workers, it must be admitted that olf ac- 



