rr^H-ttrJU*-**'
                       RELATION


CHEMICAL  CONSTITUTION  j>F  BODIES   TO; TASTE.
                               J
              By Prof. E. N. Horsford, of Harvard.
  Prof.  Horsfqrd alluded  to  a  paper upon  G-lycocoll published in
1846, in which he called attention, in a note, to the interesting rela-
tion sustained by that body  in its chemical constitution, to other sweet
bodies, and cited the following formulae :
°>^
    C4H3Ho3=GlycocoH.       .,?_

C4 H3^05  + 3= Grape sugar.       '*7 •   *  *  *
                    C4H3,P)b03=Sugarof lead.

                  C4 H 3H     03 = | Oxide of glycerile.
                        HfOi

  To this enumeration of sweet bodies  was appended the query, " Is
this  similar  taste  dependent upon a  similar arrangement of their
minutest particles ?"
  Prof. H.  remarked that, early in 1848, he presented to the American
Academy of Arts and Sciences, with a modification of the formula,  an
additional list of sweet bodies.  Some of the formulae were arbitrarily
doubled from the received formulae, and others fractionally reduced, for
the sake, merely, of tracing this interesting relationship.
  The  modification of the formulae, and the list as then presented,
were as follows :                                              » 
      C4H404 X 3 = Grape sugar.

             H
        C4H3H03 =  "
             0

             H
        C4H2H03 = Glycocoll.
             N
             Pb
        C4H2H 03 = Sugar of lead.
             0

           0
       C4H2Pb03'3 = Citrate of lead.
           O

              0
         C4H2K03 = Acetate of potassa.
              O

        H
   C.H, H02, H, 0, = Nitric ether.
        N

      H
C4H2 H    03 X 1-5 = Oxi<fe»of Glycerile.
HfOj
CI
C.H, C1CL -r- 2== Chloroform.
  4  2    CI

         Br
C4H2 Br Br3 -r- 2 = Bromoform.*
 C4H2II3-r 2 = Iodoform.
       I

      I
C4H2 I Cl3 -^ 2 = Chloroiodoform.
     CI
 Br
 B
I
C4H2 Br I3 -r- 2 = Bromoiodoform.
  * For the observation that this and the following four bodies may be included
under this type,  the  author acknowledged his indebtedness to his assistant,
Dr. Chas. H. Peirce. 
3
                   HH
             C4H2 HS t2= Hydrofluate of methylene.*
                   H  2
                   S
              C4H2 8 S3 -r  2 = Sulphoform.
                   S

                   hh
              C4H2 Hr1-r 2 = Chloride of Methyle.
                   Hul*

            C     °
            q2H2 Ag03, H,  O, — Methylsulphite  of silver.
            ba   0

            C      °
            q3 Ha Pb, H, 0,  = Methylsulphite  of lead.


              g 3A CI 03, H, 0 = Chloro-methylsulphite of silver.


              g^OlO^O-      «         «       lead.

                   O
            S4 Ag2 0 0, t2 = Hypo-sulphite of silver.f
                   0

                      N °
                   S4 fra O 03 = Hypo-sulphite of mercury and soda
                       &0

   To these Prof. Hoksford remarked there might  be added

                 C4 H2 q3 03-3 + H2 = Mannite ; and
                            C4H4S4.

Several other compounds of sulphur with C4 H4 do not taste sweet..
   The following sweet bodies, one possessing a multiple and the other
nearly a multiple of the number of atoms in Glycocoll, do  not readily
admit of being written in the  above formula—

            C, 0 H,, 03 =  24 = Valerianic acid.
             C,6Hn 07=34 = Orcine.

  * This body has a pleasant etherial smell.
  f The correspondence in constitution of this body with  the next in succession
<nves additional interest to the formula.
( 
4
   In reply to the inquiry as to whether sweetness may be ascribed to
 a peculiarity of form, the following facts are of significance:

          C4 H4 S4 tastes sweet, and contains C, H and S.
          C4 H4 04      "            "     C, H and 0.

         S„ ?2  04      "            "     neither C nor H.
          *Ag2   4

   The taste is, therefore, not dependent upon any one of the elements
 present,  since each  may be replaced entirely by another without de-
 stroying  the taste.
   In the communication submitted to the American Academy, atten-
 tion was  directed to the common formula, in which, according to Daw
 and to most modern chemists, all the acids  containing hydrogen may be
 written, and also the oxygen acids which ordinarily exist in combination
 with an atom of water, as sulphuric and nitric acids ; to wit, H + x ; in
 which x represents all that part of  the acid not replaced by  metal in
 neutralization.  A few examples follow :

 H + CI   = Hydrochloric acid. H + N0„        = Nitric  acid.
 H + I    =Hydriodic     "   H -f C2H04     = Formic "
 H -f- Br   = Hydrobromic  "   H + C204       = Oxalic  "
 H -f- F   = Hydrofluoric   «   H + C4II304    = Acetic  "
 H + Cy   = Hydrocyanic   "   H + C6H504    = Metacetonic "
 H + S 03 = Sulphurous    "   H + C8H704    = Butyric. "
 H + S 04 = Sulphuric     «   H +0,^,0,= Valerianic "  &c.

  The inquiry naturally arises,  have sour bodies a common form ? to
 which, and.not to the nature of  the constituent particles, the property
of sourness is to be attributed.   They (the acids) are composed of one
larger atom, or group  of atoms united  to  the  least atom, hydrogen,
easily  replaceable  by a metal,  and bound to the group by an affinity
apparently much feebler than that of any of the remaining" elements."
  An allusion was made, in the communication to the Academy, to  the
 class of resins—some of the soluble members of which possessing a
 bitter taste—might,  according  to a research of Heldt  upon Santo-
mne, be  referred to a single  fundamental type.  He refers the resins,
 for their origin, to the oxidation  of  the essential oils," and though  the
 conception has been entertained  by other chemists, it has first met with
 a full exposition in this paper.  The hydrogen of essential oils oxidates, 
5
as a general thing, much more readily than the carbon.  The following
formulae present Heldt's view of the production of resins.   All are de-
rived, he conceives, from Cj 0H8.

              [C10H8]° — Hx+Ox = R.
              [C10H-8]» — Hx + Ox + (H0)y= R.
              [C10H8]» — Hx + Ox + Oy = R.
              [C10H8]n _ Hx + Ox + Oy + [HO]z= R.
              [C10H8]n + [H0]x = R.

   These formulae present in the original  essential oils, groups of atoms,
in which a part of the hydrogen occupies  a more exposed situation, if
.one may employ the illustration, than other parts of the molecule, and
oxidates more  readily. In this respect there is approximation to a
common form, in view of  which the inquiry was suggested, may the
bitterness be ascribed to this form ?   This, however, does not furnish an
explanation of the remarkable bitterness of the organic bases.
   Guided  by the above  suggestion, Prof. H. remarked,  let the con-
ception be  entertained that the alkaloids have been derived, from the
greater or less oxidation of bodies having the general constitution of
the essential oils, and  the replacement  of three  atoms of water with
one atom  of ammonia for every atom  of nitrogen  contained in the
organic base.  The corresponding replacement of ammonia with three
atoms of water is not of unfrequent occurrence in organic chemistry.
   Upon the speculation that this has been  the derivation of the alka-
loids, it will be  easy  to convert them into the essential oils from which
they  were  derived.  If we halve the  formula of the oil,  the first of
Heldt's formulae gives

                    (C5H4)n —Hx + Ox = R.

A certain number of atoms of hydrogen deducted from, and an  equal
number of  atoms of oxygen added to, n times  CSH4 constitute the
resin.   If, in adding  nitrogen,  we deduct  for each  atom of nitrogen
three atoms of  oxygen, or, which is the  same thing, for each atom of
ammonia (NH3) added, deduct three atoms of water, we have an or-
ganic  body  containing C, H, N and 0,  a  body corresponding in con-
stitution with an alkaloid.
   By reversing this process, we may convert the alkaloid into  its cor-
responding essential oil. 
6
  Take for example Papaverin, one of the alkaloids of opium, analyzed
by Merck.  C40H2INO8.*
  Three atoms of oxygen for the atom of nitrogen, united to the eight
atoms of oxygen, making eleven in all, correspond  with eleven  atoms
of hydrogen, which, added to the twenty-one present, make thirty-two.

     C40H21NO8 —N —0, + H8 + 03 — C40H29 + 0X,

which correspond with
                     C40H32=(C5H4)'.

  There is  doubt  still  resting upon the constitution  of most of the
alkaloids.  Of those  considered as best established, the following ex-
amples will  be sufficient for a practical illustration of the above specu-
lation.
       Thebain = C25 H14 N03 = C2SH20 = (CSH4)6.
       Furfurin= C30H12N2O6 =C30H24 = (CSH4)«.
       Codein = C3SH2 0NO5 = C3SH2 8 = (C5H4)7.

  The formula (CSH4)" — Hx + 0X + 0y =R,  is suited to the de-
rivation of Bebeerin.

            C35H2 0NO6 =C35H29 =(C5H4)T  + H.

  Harmalin requires the  addition of C2H2 to  the second of Heldt's
formulae (CSH4)  —H  +Oy=R.

        C27Hl4N202=C27H22 = (CfiH4)6-f-C2H2.

  Chinin and Cinchonin require the subtraction  of C2.

     Chinin=C38H22N204t=C38H32 = (CsH4)e-C2.
  Cinchonin = C38H22N204J=C33H32 = (CsH4)8-C2.

  Strich'nin  requires the deduction of an atom of carbonic acid, or its
equivalent CH2, and the same formula of resin  as that of Bebeerin.

         C44H24N204 = C44H34=(CsH4)9-CH2.

  Cotarnin requires the addition of an atom of  carbonic acid.
* Liebig's Ann., LXVL, 125 ; Pharm. Contr., 1848, 930.
f Ann! Ch. Phys. [3] XIX., 363; Ann. d. Ch. u. Phar. LXIL, 95.
X Ann. Ch. Phys. [3] XIX., 365. 
7
          C26Hl3N08* = C2flH22 =(C5H4)'+ CH2.

  The following require slight modifications.

  Morphin = C34H19N06t=C34H28 = (CsH4y-C.
  Piperin = C34H19N06t=C34H2 8 = (CSH4)'-C.
  Veratrin = C34H23N06 = C34H31 - (C5H4)'- C + H3.

  It will readily be seen that in this series the differences between the
essential oil and its derivative  are  such as would disappear with the
addition or subtraction of an atom of carbonie  acid, or water in  some
cases, and a little more or less oxidation in others.
  In those bases  where  the quantity of nitrogen is much  larger, the
third formula of Heldt would still give us the corresponding  resins.

                (CSH4 )a — Hx + Ox + Oy = R.

  Take for example Caffein.

                         CI4H8N404.

  The nearest essential oil of  the constitution (CsH4)n is C1SH12.

  Cl5H12-H4-f-04+014-f-4(H3N)-12H0 = ClsH8N406.

  If we deduct from this formula an atom of carbonic acid, we have

               C15H8N406-C02=C14HsN404.

  Theobromin  differs, as  has  been  remarked,§ from  Caffein only
byC3H2.

             C14H8N404 +C2H2==C16HloN404.

  The construction from the class  of oils,  above referred to,  of  the
formulae  of those alkaloids  in  which the quantity of  hydrogen is much
greater, is more difficult.
  The foregoing relationships have an interest taken in connection with
the inquiry to which attention has been directed, to wit, May there be a
common form among bodies having  a common taste ?

  * Ann. Ch. Phys. [3] XIX, 3*70.
  f Ann.  Ch. Phys. [3] XIX, 361; Ann. d. Ch. u. Phar. LXIIL, 98.
  % Ann.  Ch. Phya [3] XIX, 363.
  § Ann. d. Ch. u. Pharm., LXI., 338?  Pharm. Cont Blatt, 1847, 424.