ELISHA MITCHELL SCIENTIFIC SOCIETY. 35 



it is more far-reaching into the realm of Nature's little things 

 than the most powerful instrument devised to aid the eye. How 

 infinitesimally small must be the particles which for years arise 

 IVom the few grains in a box of musk, and yet the sense of 

 smell can unerringly detect them. How tiny the particles of 

 perfume rising fi'om some small flower and scenting the breezes 

 for hours — that is, conferring fragrance upon many miles of air. 

 Still how easily the delicate nostril detects the presence of the 

 sweet fragrance. 



This would seem to open up a new field of work for the ana- 

 lyst, offering him most delicate assistance, and indeed Dr. 

 Crookes suggests as much, but unfortunately, though so easily 

 affected by some substances, the great majority of them do not 

 affect the organ of smell at all, or in very slight degree, no 

 matter in what quantity they may be used. So far as the quan- 

 tity of matter is concerned, it is usually the case that the smell 

 becomes less and less apparent as the quantity is increased, after 

 a certain limit is reached. If too much ottar of roses or hydro- 

 gen sul})hide be used, the sense of fragrance or of its opposite is 

 largely lost. 



Turning now to the sense of taste, the last of these senses to 

 be investigated, I can find no reported experiments upon its 

 delicacy. Apparently only a few approximate statements have 

 been made with regard to one or two substances. I have with 

 some care experimented upon this point with a few characteristic 

 substances, utilizing the sense of taste of two persons so as to 

 partly eliminate personal errors. Known weights of the sub- 

 stances, dissolved in the pro})er solvent, were diluted until the 

 taste was barely perceptible, a slight further dilution causing its 

 disappearance. The results show the sense of taste much less 

 delicate than that of smell. Of sugar, y^^Q-g- of a gramme barely 

 tastes; of salt, j-^^; of acid (hydrochloric), xordo"? *^^ saccha- 

 ^'•'^ 1000000 ^ ^i"^l ^f strychnine j^-^5___^ ^f .^ gramme gave 

 barely a perceptible taste, and this was the greatest delicacy of 

 taste, or persistency of taste, reached with the substances experi- 

 mented upon. Tf we compare the delicacy of taste towards 



