On December 8th, 1853, a bullock’s heart weighing 1240 grammes,
without removing its fat, was buried in sand in an inverted tubulated
receiver held in a retort stand, and so placed against the glass that
a portion of it could be seen: a reservoir of water was placed above
the receiver, and this water was suffered to fall, drop by drop, upon
the sand by means of a syphon of lamp-wick. The water was removed when
necessary, and the changes appearing in the heart observed. These
changes were the same as in the case of the bottled experiments; it
began soon to deepen in colour, and on May 11th, 1854, was quite dark,
while the liquid falling from the receiver contained a black amorphous
precipitate, which is probably, from Liebig’s observation of a similar
case, sulphuret of iron. A deep zone of green vegetable parasitic
matter was visible around the inside of the receiver, commencing within
half of an inch above the position of the heart where it was deepest
in colour, and thence diminishing as it approached the surface of the
sand. On June 7th, the heart was removed and dissected for the purpose
of viewing the extent of the decomposition: it maintained its original
form, but was larger; the separation of the chambers was apparent;
the valves present and the chordæ tendineæ in a perfect state; the
greater part of the fleshy walls of the heart was pinkish, soft, of the
consistence of lard, of putrid smell, and under the microscope (700
D,) presented an amorphous mass, mingled with fragments of crossed
muscular fibre. It was not in as advanced a stage of decomposition as
the bottled hearts of December 13th, 1854. The fat which was purposely
left around the coronary vessels, was hard, white, and of an appearance
approaching that of adipocire. The heart was returned to the vessel and
the experiment continued. On my return to the city, after an absence
in the summer time, I found that the water reservoir and lamp wick had
fulfilled their duty, for the sand was still moist. On December 9th,
1854, the experiment was concluded, and the heart removed from the sand
and washed. It was in two pieces, and weighed, when still wet, 219
grammes: after drying in the air for five days it weighed 107 grammes,
or 8·6 per cent. of the original weight, and was still moist. This was
principally the fat from around the coronary vessels, the impressions
of which were on it; the tendinous chords of the valves were perfect,
and the valves themselves were indicated. The smell was decidedly
tallowish, with the strong smell I have described as adipocire smell,
and with the smell of earth worms; all of these odours were plain,
and suggested themselves at once to the mind. The fat was hard, and
resembled exactly adipocire; it presented a different appearance in
two different places: one portion was hard and compact, in some parts
denser, in others lighter than water, and appeared granular under the
microscope, like the specimens of adipocire already described: the
other portion was of a more buttery nature, and of about the density
0·8365. Neither of these specimens gave any traces of fat globules
with the microscope, but contained aggregations of white angular fatty
matter, of nearly the same size, and about one fourth the diameter
of fat globules. With ether the fat disappeared, and left shrunken
membranous matter, which after the evaporation of the ether and
treatment with acetic acid, became, for the most part, transparent. A
comparative experiment with beef fat gave similar results, and I am
inclined to think that the most of this matter proceeds from the fat
cells,[9] and their accompanying cellular tissue.
On cutting through the thickest portion of this adipocire, the fat was
of a pure white colour, and could not be distinguished from adipocire;
in some portions it was nearly an inch in thickness, and at first
sight certainly gave the impression that the fleshy walls of the heart
were converted into fat; but on closer inspection, this seemed to me
improbable. The lumps of adipocire were thickest at the top of the
heart, and just where were the lumps of fat in which the coronary
vessels were imbedded; moreover, it was the most like adipocire in
the centre of those very portions of fat. I obtained the approximate
density of the adipocire of this part, by diluting alcohol with water,
until the adipocire just swam half way between the surface and the
bottom of the liquid, and found it to be 0·8902, which is by experiment
lower than that of ox fat. Indeed, as would a priori seem probable,
the fat, by the gases evolved during the putrefaction of the proteine
bodies, is rendered more porous, and of a lower specific gravity,
which deceives the eye, and makes the mass of fat to appear greater
than it really is. An ash determination of this part of the adipocire
performed upon 1·471 grammes, yielded 0·0015, equal to 0·102 per cent.
of a reddish ash, containing iron. No acroleine was observed during
this experiment, and no other than the characteristic adipocire smell,
which proves the absence of glycerine, and that the fatty acids are
uncombined. Ox fat (2·069) gave (0·001, or) a per centage of 0·048
white ash. The iron of the former proceeds probably from the hæmatine
in the heart. These ashes are too small in quantity, to arrive at any
satisfactory result in ascertaining the nature of their component
parts; they appeared by a few tests to contain principally lime, and
soda and potash were detected by Smith’s test. The melting point of
the above portion of adipocire was about 47°, but at 52° the fat still
contained a faint precipitate.
The adipocire, on February 3d, 1855, until which time it had been kept
in a loosely stoppered bottle, weighed 97 grammes, which is 7·8 per
cent. of the original heart. From 91 grammes the fat was separated
by boiling it with 317 alcohol, filtering hot, pressing powerfully,
and weighing the residue; the latter was bulky, and weighed 40·1,
corresponding to 44 per cent. of the _adipocire_, which contains,
consequently, only 66 per cent. of fat. If the per centage of fat be
calculated from the original weight of the _heart_, it amounts to
only 4·4, which is undoubtedly less than was originally in the heart,
so that, so far from there being a gain of fat in the formation of
the adipocire, there was actually a loss, which accords with the
bottle experiments. The alcoholic solution deposited 16·2 grammes
of a rather dark fat, which was recrystallized from 368 grammes of
alcohol, and yielded 11 grammes of a lighter fat. I was desirous of
retaining a greater portion of this fat for future experiments, and
without proceeding to purify it further, obtained its equivalent. It
melted between 69°-70°, did not crystallize plainly from alcohol, with
which it behaved like stearic acid: a neutral silver salt, deepened
in colour considerably when dried at 100°, and gave only 20·59 and
20·68 per cent. of silver. As decomposition had evidently taken place
in this salt, the baryta compound was prepared by adding acetate of
baryta to the alcoholic solution. The baryta was determined both as
carbonate and by converting into sulphate; there was no difference
in the two results; the baryta of the carbonate was 0·1701, and that
of the sulphate was 0·1700, which corresponds to a per centage of
19·65--stearic acid (Heintz) requires 21·76 per cent., and palmitic
acid 23·62 per cent. of baryta for the neutral salts. I have no doubt
that a further purification will show this to be stearic acid, as might
be expected from the original fat of the heart.
I am not desirous of claiming for these experiments a greater
importance than they deserve, nor any but that the experiments were
carefully performed: they were extended over the greater part of a
year, during which my attention has been particularly directed to
this subject. When the investigation was commenced, I was inclined
to the belief that adipocire was a result of the decomposition
of the blood-forming substances, and this, principally, from the
experiments of Blondeau (see first part of this article) which I have
not seen refuted, and partly from the testimony of those who have had
opportunities of observing the formation of adipocire, and who have
stated that fleshy parts of the body are wholly converted into it.
The formation of the lower terms of the series of fatty acids from
proteine bodies forbids maintaining that this is impossible; but from
what I have seen, and on weighing the evidence of what I have read, my
impression is, that adipocire proceeds from the original fat of the
body.
It appears to follow from the foregoing experiments, that the
higher members of the series of fatty acids do not result from the
putrefaction of proteine compounds; at least from such putrefaction
as is accompanied by exclusion of air. Flesh fibrine with restriction
of air does not putrefy as rapidly as would be supposed, according to
the experiment, where a portion was sealed with water on a microscope
slide; the air here was not absolutely excluded, since a partial
evaporation of the water took place. It is true that the amount of
water in this experiment was small, in proportion to the fibrine,
and it appears that much water is necessary to such decomposition,
and which supports Liebig’s theory of the motion of the molecules.
In the experiments of the bottles and of the sand, the decomposition
was _seen to take place_ gradually; the sarcous element of the flesh
fibrine separated into discs, and these were by degrees resolved into
their simpler compounds, which either remained as liquids or gases
in solution in the bottles, or were carried off by the droppings
in the sand experiment. The original fat of the body, according to
circumstances, either partakes of this decomposition, or else, losing
its glycerine and most of its oleic acid, becomes gradually converted
into adipocire. In some bodies in the grave yards the fat is totally
gone, while in others large quantities of adipocire are formed. It is
suggestive that in all cases where adipocire has been found, the corpse
was of a large and fat person, and this abundance of fat resists an
ultimate decomposition. Analyses by Beetz of candles which had remained
for a hundred years in a mine, prove that the only alteration undergone
by fats when alone, is destruction of their oleine and glycerine.
In the bottles of my experiments no adipocire was formed, although
the fat of the coronary vessels was only partially removed; this
may be accounted for on the ground that the fat, which was small in
quantity, was here kept in close contact with the decomposing fibrine,
and suffered with it decomposition, whereas in the sand experiment,
this could only take place to a less degree. In grave yards, if the
proportion of flesh to fat be large, and especially if the ground be of
such a nature as to prevent the decomposed matter being carried off,
as by draining, adipocire cannot be formed, but the fat undergoes full
decomposition.
The fact that in adipocire from different animals, the same substances
are found accompanying the original fat of the animal, as the goat-like
or mutton smell in sheep, and the tallow smell of the fossil adipocire,
is suggestive, and should shift the burden of experimental proof upon
those who maintain the formation of this substance from fibrine. The
microscopic experiments militate against the transformation from
fibrine. Those that believe in this change think to have proof from
the shape, as it were, of certain muscles transformed into fat;
but fibrine does not require to lose much substance in the shape
of ammonia, &c., for this transformation, and there would not be,
therefore, a great disturbance in the shape of the fibres of muscle; at
any rate, it would be reasonable to expect, that with the microscope,
traces of an arrangement of the fatty particles into fibres or rows
would here and there be seen, but this is not the case, and the
appearance is that of fat particles of equal size among themselves,
and of a diameter one-fourth that of the original fat globules, and
indeed presenting all the appearances to be expected from a mass
of fat undergoing alteration from the decomposition of its oleine
and glycerine; and finally in the experiment where adipocire was
artificially formed, no gain of fat was observed, but a loss of what
was purposely left upon the specimen under examination.
I shall delay an examination of the products in my hands, until the
separation of the fatty acids is improved. It would be easy enough
with the present methods to isolate the two principal constituents of
the fatty acids from the material in hand; but small quantities of new
products would inevitably escape observation.
The _desiderata_ in working the fatty acids at present, are, First,
separation of the oleic acid, without too much loss of substance.
Second, a less circuitous method of separating the fatty acids than
by Heintz’s method, which renders difficult the isolation of small
quantities of a different acid, as shown by his mistake of anthropic
acid.
It is probable that a crystallization of salts (especially with
a base of a high equivalent) would effect this purpose, for in
crystallization, other compounds and impurities are concentrated in
the mother liquids, while in fractional precipitation, in the present
case, an infinite subdivision seems to take place, requiring many steps
to accomplish a sufficient purification; and brilliant as Heintz’s
results are, considerable labour was required to arrive at them.
Heintz’s process of partial precipitation was founded upon the method
of fractional distillation, proposed by Liebig for the separation of
the lower members of the series of fatty acids; in the latter case
presence of an alkaline carbonate, in quantity insufficient to saturate
the mixed acids, alters their volatility, while in the former, presence
of a salt in insufficient quantity for perfect decomposition changes
the relations of _solubility_ of the salt formed, and it does not
necessarily follow that the chemical affinity, active in both cases,
will afford as _expeditious_ a method in cases of solubility as in
those of volatility.