248 THE JOURNAL OF PHARMACOLOGY. 



(in 1890, and again in 1895) has likewise referred to this topic, whicli 

 he rightly esteems as one of fundamental significance. 



Bit by bit — here a little, there a little — we are gathering the kind 

 of material which can best help us to gain insight into the principles o? 

 therapeutics. 



True, we may have to wait a good while before a stately edifice can 

 be built up, but none the less does it hold true that the problems of thera- 

 peutics, and for that matter of all biology, are, at the root of things, es- 

 sentially chemical or physico-chemical, or in so far as we are at all able 

 to interpret them, or refer them to general laws. 



To give an example or two : — 



Some of the fatty hydrocarbons are in themselves tasteless, but let us 

 mtroduce the radicals Oil (hydroxyl), NH2 (amidogen), or NO2, and 

 io ! we get color, odor, or taste conferred upon the molecules. 1-or a 

 compound to have a sweet taste it must contain at least two oxygen 

 atoms (and every electro-positive group must be united to an electro- 

 negative group). Thus all polyatomic alcohols are sweet (i.e., glycol, 

 glycerine, etc.), and aromatic sugars. f.»"., have a bitter taste (Stern- 

 berg, Cheni. Ccntralbl, 1899). 



CO 

 Again, look at the groupQH^<^^TT — viz., ortho-benzoylimide. As 



including it we have these compounds : — 



CO OH 

 I. — Anthranilic acid, C6H^< ^^ ' „ ' and its methylester, 



C„H.< XTTT ^ has a smell of orange blossom oil. 



•■ * NH, *^ 



p TT .^ ^--^P 



2. Indigotin, CibHi„N,.0„< p^ || has an intense blue color. 



C H <r ^C 



CO 



3. Saccharin, C6H^<^p. >NH, is an intensely sw^e/ substance ; and, 



lastly, 



CO 



4. Ox-indole, C.H.NO C6H^<j^„>CH2 is a constituent of essential 



oil of jasmine flowers, associated with anthranilic methyl-ester. 



So we find that different effects produced upon the senses of smell, 

 fisfe, and sight are coincident with differences of arrangement in the 

 molecules of the respective compounds, which are all built around a com- 

 mon nucleus (Watson Smith). 



Innumerable difficulties still await an answer — e.g., why should sac- 

 charin, which is an "ortho"' compound, be so sweet, while the "para" 

 compounds are devoid of sweetness? Still we can assert that great 



