July 6,1372.] 
THE PHARMACEUTICAL JOURNAL AND TRANSACTIONS. 
5 
from organic substances, whilst methyl and formyl com¬ 
pounds were included amongst them. As soon as the true 
atomic weight of carbon was established, Gmelin s defi¬ 
nition fell to the ground. It was then said that organic 
chemistry was simply the chemistry of the carbon com¬ 
pounds. Kekule, who first distinctly advocated this 
view, says (‘ Lehrbuch,T),.“ There is no natural boundary 
line between organic and inorganic chemistry, and if we 
still retain this division, it is only as a matter of conve¬ 
nience. We treat the carbon compounds separately on 
account of their large number and their importance. 
Erlenmeyer expresses similar views. He thinks 
(Lehrb. d. Org. Chem. 5) “that a division of labour is 
requisite in the interest of teaching. “ Besides, he 
adds, “ it cannot be denied that by reason of certain pro¬ 
perties possessed by carbon, the caa-bon compounds exhi¬ 
bit several peculiarities in their chemical behaviour, so 
that their study requires in many respects other methods 
of investigation than those employed in the study ol the 
compounds of the other elements, and thus the necessity 
for a division of labour has also made itself apparent 
in the interests of scientific research. 
Butlerow^also says (Lehrb. d. Org. Chem. 5), “ Organic 
chemistry must now be defined as the chemistry ot the 
carbon compounds. If such a definition is somewhat un¬ 
natural and not exactly correct, it is still very conve¬ 
nient ” I think, however, that such a division is more 
than a mere matter of convenience. The compounds of 
carbon do really differ from those of the other elements, 
because carbon itself exhibits certain properties which no 
other element possesses. 
Kekule, who first showed that carbon is a tetrad 
element, pointed out at the same time that the exist¬ 
ence of such an immense number of carbon compounds 
can be easily explained by assuming that the atoms of 
this element have the property of combining with each 
other. The same view was expressed by Gouper. 
This property is also possessed by other polygenic ele¬ 
ments, as sulphur and oxygen; but whilst, in the case of 
the latter elements, the number of atoms uniting to¬ 
gether in this way is very limited, we have not yet 
found such a limit to exist in the case of carbon. 
It is, therefore , most characteristic for tetrad carbon that 
a large number of its atoms can be linked together to form a 
group , which in a great many reactions remain togetnei , and 
act like a single atom. 
But carbon possesses yet another property in common 
with no other element. -A.il the combining units in such a 
group , which are not saturated with carbon , can be saturated 
with hydrogen. 
Thus, whilst most of the metals do not combine with 
hydrogen at all, and the other elements form only one or 
two, or at the most three compounds with hydrogen, we 
find not only that very many hydrocarbons exist, but 
that their- number is daily increased by the discovery of 
new ones. 
The hydrocarbons arc not only the most simple oi.tne 
carbon compounds, but, from a theoretical point of v iev, 
also the most important, because all other. carbon com¬ 
pounds can be regarded as derivatives of them, oi as 
bein°- formed by substitution of other elements, foi h\ - 
drogen. This is shown by the fact that a considerable 
number of vegetable and animal substances can be pre¬ 
pared artificially from hydrocarbons. On the other- 
hand, as soon as the constitution of a carbon compound 
is understood, we are in a position to convert it into the 
hydrocarbon from which it has been theoretically de¬ 
rived. 
In the majority of carbon compounds occurring in 
nature, a portion of the hydrogen of the original hydro¬ 
carbon is replaced by oxygen, and in others by nitrogen, 
all the other elements can, however, be introduced artifi¬ 
cially into carbon compounds. But there are onl} a few 
cases in which all the hydrogen can be replaced. 
Thus, the number of carbon chlorides is much smaller 
than that of the hydrocarbons. AVith oxygen, carbon 
forms only two compounds, and with nitrogen it unites 
in only one proportion. From this it follows that the 
great majority of carbon compounds contain hydrogen,— 
that there is present in them a residue of the original 
hvdrocarbon. 
“AVe may, therefore, define that, part of. our science 
which is commonly called organic chemistry as the 
chemistry of the hydrocarbons and their derivatives. 
I now propose to lay before you, in a short sketc-li, 
how far our knowledge of the * hydrocarbons has ad¬ 
vanced. 
[To be continued.) 
SULPHOZONE, A SUBSTITUTE FOR SULPHUR. * 
BY CHARLES ROBERTS, F.R.C.S., ETC. 
Sulphur in the sublimed, precipitated, or powdered 
form, is extensively employed by medical men,, veteri¬ 
nary surgeons, and horticulturists, for destroying the 
animal and vegetable parasites infesting man, animals, 
and plants. The substance to which I have given the 
name of sulpliozone (from its strong smell and pow ci fm 
chemical action), in order to distinguish it from the 
sulphur of commerce, is a preparation containing free 
sulphurous acid as its active and essential principle. 
For many years past large quantities of. sublimed and 
powdered sulphur have been used in this country and 
on the Continent, for the destruction of the mildew and 
blight attacking vines, hops, roses, fruit and other trees.; 
and it is now r , I believe, almost the sole remedy em¬ 
ployed for that purpose, as no other has been, founu 
so generally effectual or so convenient of application. 
From careful and often repeated series of experiments, 
I have arrived at the conclusion that the beneficial 
action is to be attributed to the presence, of a small but 
variable quantity of free sulphurous acid (occasional!} 
hyposulphurous acid), which exists as a constant im¬ 
purity in the sulphur of commerce. Sublimed sulphur 
contains more acid than powdered crude sulphur, and lh 
more certain in its action, while precipitated snip nu, 
being almost, or altogether, free from acid, is quite 
useless. I find that when substances . are carefully 
purified from all traces of sulphurous acid by repeated 
washing with spirit and water, they are equallv lneftec- 
tual in destroying mildew and other. vegetable . and 
animal organisms, and that seeds germinate as quick } 
and vigorously when sown in pure sulphur as in fine 
sand, and that moulds grov r on the surface when a little 
organic matter, as Hour, has been mixed with the sulphur. 
I find also that cheese mites are not destroyed by pure 
sulphur, but live and multiply indefinitely m cheese 
covered with sulphur; though they are immediately 
destroyed by commercial sublimed sulphur. On the 
other hand, when pure sulphur is impregnated with sul¬ 
phurous acid, it destroys mildew, and other minute 
organisms with an energy proportioned to the quantity 
of acid it contains, and it does not appear that one ten in 
of sulphur possesses any advantages over the o.-her.j, 
provided the quantity of acid is uniform. Many other 
substances which contain no sulphur, when impregnatett 
with sulphurous acid in a similar manner, and to tha 
same extent, are equally effectual in destroying mi.~ 
dC It has been observed that when a piece of silver-leaf 
is suspended over a roll of sulphur, it is slowly converted 
into the sulphide of silver, and it has. been inteire 
therefrom that sulphur vapourizes at ordinary tempera¬ 
tures- and the theory has been advanced by a veil- 
known vegetable physiologist,, that the oxygen g^e* 1 o 
by the leaves of plants to which sulphur has been M 
plied, oxidizes it and produces sulphurous and, andL thus 
the action of sulphur in de stroying vegetable oi 0 annms 
* Paper read at the Meeting of the Royal Horticultural 
Society at Birmingham. 
