
276 

containing an excess of aniline. We have also from Stenhouse 
a new contribution to the history of orcin, in continuation of his 
former masterly researches on that body. He has prepared the 
trinitroorcin (C,H; (NO,)3, O,), a powerful acid having many 
points of resemblance to picric acid. In connection with another 
research of Stenhouse, made many years ago, it is interesting to 
find his formula for esexanthron, which was also that of Erd- 
mann, confirmed by the recent experiments of Baeyer. 
The interesting work of Dewar on the oxidation of picoline 
must not be passed over without notice. By the action of the 
permanganate of potassium on that body, he has obtained a new 
acid, which bears the same relation to pyridine that phthalic acid 
does to benzol. Thorpe and Young have published a pr: liminaty 
notice of some results of great promise, which they have obtained 
by exposing paraffin to a high temperature in closed ves-els. By 
this treatment it is almost completely resolved into liquid hydro- 
carbons, whose boiling points range from 18° C. to 300° C.; 
those boiling under 100°C. have been examined, and consist 
chiefly of olefines. In connection with this subject, it may be 
interesting to recall the experiments of Pelouze and Cahours on 
the Pennsylvanian oils, which proved to be a mixture of carho- 
hydrogens belonging to the marsh-gas series. 
An elaborate exposition of Berthelot’s method of transforming 
an organic compound into a hydrocarbon containing a maximum 
of hydrogen, has appeared ina connected form. The organic 
body is heated in a sealed tube, with a large excess of a strong 
solution of hydriodic acid, to the temperature of 250°. The 
pressure in these experiments Berthelot estimated at 100 atmo- 
soheres, but apparently without having made any direct measure- 
ments. He has thus prepared ethyl hydride (C, Hg) from 
alcohol, aldehyde, &c. ; hexyl hydride (Cg H,,) from benzol. 
Berthelot has submitted both wood charcoal and coal to the re- 
ducing action of hydriodic acid, and, among other interesting 
results, he claims t» hive obtained in this way oil of petroleum. 
By the action of chloride of zine upon codeia, Matthiessen 
and Burnside have obtained apocodeia, which sands to codeia 
in the same relation as apomorphia to morphia, an atom of water 
being abstracted in its formation. Apocodeia is more stable 
than apomorphia, but the action of reagents upon the two bases 
is very similar. As regards their physiological action, the hy- 
drochlorate of apocodeia is a mild emetic, while that of apo- 
morphia is an emetic of great activity. Other bases have been 
obtained by Wright by the action of hydrobromic acid on codeia. 
In two of these bases, bromotetracodeia and chlorotetracodeia, 
four molecules of codeia are welded together. so that they con- 
tain no less than 72 atoms of carbon. They have a bitter taste, 
but little physiological action. The authors of these valuable 
researches were iniebted to Messrs. Macfarlane for the precious 
material upon which they operated. 
We are indebted to Crum Brown and Fraser for an important 
work on a subject of great practical as well as theoretical inte- 
rest, the relation between chemical constitution and physiological 
action. It has long been known that the ferrocyanide of potas- 
sium does not act as a poison on the animal system, and Bunsen 
has shown that the kakodylic acid, an arsenical compound, is 
also inert. Crum-Brown and Fraser find that the methyl com- 
pounds of strychnia, brusia, and thebaia are much less active 
poisons than the alkaloids themselves, and the character of their 
physiological action is also different. The hypnotic action of 
sulphate of methyl-morphium is less than that of morphia. But 
a reverse result occurs in the case of atropia, whose methyl and 
ethyl derivatives are much more poisonous than the salts of 
atropia itself. 
Before proceeding to the subject of fermentation, I may refer 
to Apjohn’s chemico-optical method of separating cane sugar, 
inverted sugar, and grape sugar from one another when present 
in the same solution, by observing the rotative power of the syrup 
before and after inversion, and combining the indications of the 
saccharometer with the results of an analysis of the same syrup 
after inversion. Heisch’s test for sewage in ordinary water is 
also deserving of notice. It consists in adding a few grains of 
pure sugar to the water, and exposing it freely to light for some 
hours, when the liquid will become turbid from the formation of 
a well-marked fungus, if sewage to the smallest amount be pre- 
sent. Frankland has made the important observation that the 
development of this fungus depends upon the presence of a phos- 
phate, and that if this condition be secured, the fungus will 
appear even in the purest water. 
The nature of fermentation, and in particular of the alcoholic 
fermentation, has been lately discussed by Liebig with consum- 
NATURE 



(Aug. 3, 1871 

mate ability, and his elaborate memoir will well repay a careful 
perusal. Dr. Williamson has also given a most instructive ac- 
count of the subject, particularly with reference to the researches 
of Pasteur, in his recent Cantor lectures. A brief statement of 
the present position of the question will therefore not be out of 
place here. It is now 34 years since Cagniard de la Tour and 
Schwann proved by independent observations that yeast globules 
are organised bodies capable of reproduction by gemmation ; 
and also inferred as highly probable that the phenomena of 
fermentation are induced by the development or living ac- 
tion of these globules. These views, after having fallen into 
abeyance, were revived and extended a few years ago by Pasteur, 
whose able researches are familiar to every chemist. Pasteur, 
while acknowledging that he was ignorant of the nature of the 
chemical act, or of the intimate cause of the splitting up of 
sugar in the alcoholic fermentation, maintained that all fermenta- 
tions, properly so called, are co-relative with physiological 
phenomena. According to Liebig, the developement and 
multiplication of the yeast plant, or fungus, is dependent upon 
the presence and absorption of nutriment which becomes 
part of the living organism, while in the process of fermentation, 
an external action takes place upon the substance, and causes it 
to split up into products which cannot be made use of by the 
plant. The vital process and the chemical action, he asserts, 
are two phenomena which in the explanation must be kept separate 
from one another. The action of a ferment upon a fermentable body 
he compares to the action of heat upon organic molecules, both of 
which cause a movement in the internal arrangement of the 
atoms. The phenomena of fermentation Liebig refers now as 
formerly to a chemico-physical cause, the action, namely, which 
a substance in a state of molecular movement exercises upon 
another of highly complex constitution, whose elements are held 
together by a feeble affinity, and are to some extent in a state of 
tension or strain. Baeyer, who considers that in the alcoholic 
and lactic fermentations one part of the compound is reduced 
and another oxidised, adopts the view of Liebig that the mole- 
cules of sugar which undergo fermentation do not serve for the 
nourishment of the yeast plant, but receive an impulse from it. 
All are however agreed that fermentation is arrested by the 
death of the plant, and even a tendency to the acetous fermenta- 
tion in wine may be checked, as Pasteur has shown, by heating 
the wine to a temperature a little below boiling point in the 
vessel in which it is afterwards to be kept. 
I regret that the limits of an address like the present forbid 
me to pursue further this analysis of chemical work. Had they 
admitted of abridgment I should gladly have described the 
elaborate experiments of Gore on hydro-fluoric acid and the 
fluoride of silver. The important researches of Abel on explo- 
sive compounds will be explained by himself in a lecture 
with which he has kindly undertaken to favour the Association. 
Mr. Tomlinson will also communicate to the section some 
observations on catharism and nuclei, a difficult subject to which 
he has of late devoted much attention. And I am also informed 
that we shall have important papers on recent improvements in 
chemical mauufactures, 
No one can be more painfully alive than myself to the serious 
omissions in the historical review I have now read, more par- 
ticularly in organic chemistry, where it was wholly impossible to 
grapple with the large number of valuable works which even a few 
months produce. I cannot, however, refrain from bearing humble 
tribute to the great ability and indomitable perseverance which 
characterise the labourers in the great field of organic chemistry. 
It would scarcely be possible to conceive any work more in- 
telligently undertaken or more conscientiously performed than 
theirs, yet much of it, from its abstruse character, receiving little 
sympathy or encouragement except from the band of devoted 
men who have made this subject the chief pursuit of their lives, 
They will, however, find their reward in the consciousness that 
they have not lived in vain, but have been engaged, and success- 
fully engaged, in the noble enterprise of extending for the benefit 
of the human family the boundaries of scientific knowledge. 
Noris there any real ground fordiscouragement ; Faraday, Graham, 
Magnus, and Herschel, who have left their impress on this age, 
were all distinguished chemical as well as physical discoverers ; 
and the relations of the sciences are becoming every day so 
intimate that the most special resear-h leads often to results of 
wide and general interest. No one felt this truth more clearly or 
illustrated it better than our lamented and distinguished friend, 
Dr. Miller, whose presence used to cheer our meetings, and 
whose loss we all most sincerely deplore. 
