XYI.—On the Fatty Matters of Human Excrements in Disease. 
By W. Marcet, M.D., P.C.S., 
ASSISTANT PHYSICIAN TO THE WESTMINSTER HOSPITAL, ETC., ETC. 
It has often been noticed that excessive quantities of fats are 
voided by the motions in certain diseases; but no attempt having 
been made to separate these fatty substances from each other, and 
obtain them in the form of Immediate Principles, I have under- 
taken tliis task in one case, by adopting a method of investigation 
similar to that which I had made use of for the analysis of healthy 
excrements. The case in question is that of a man who was for a 
long time my patient at the Westminster Hospital, labouring, 
apparently, under disease of the kidneys. Prom his excessive 
emaciation, it was evident that the assimilation was very defective, 
and, with the view of endeavouring to obtain some further insight 
into the nature of the disease, his faeces were submitted to exami- 
nation. They had the consistence of putty, a yellow grey colour, 
and a strongly acid reaction. When boiled with alcohol, they 
formed an homogeneous mass, which, being squeezed in a muslin 
bag, yielded a turbid alcoholic fluid; this was now filtered through 
filtering paper, and the insoluble residue exhausted with boiling 
alcohol. On cooling, an abundant crystalline deposit, quite free 
from colouring matter, occurred in the solution. In order to 
analyse the deposit, it was collected on a filter, and the filtrate 
was left to evaporate spontaneously. I removed the deposit to a 
flask, and then treated it with ether, until nothing more was dis- 
solved; by so doing, the crystalline mass was divided into a sub- 
stance insoluble in ether, and one which was soluble in this fluid. 
The substance insoluble in ether dissolved in hot alcohol, but was 
sparingly soluble in cold alcohol; the solution had an acid reaction. 
The crystals were soluble in hot water; but the addition of cold 
water to the alcoholic solution, induced the formation of a cloudy 
precipitate, and the fluid gradually became neutral. 
This compound fused at a temperature ranging between 
100° and 103° 0. When the aqueous solution was mixed with 
hydrochloric acid, the liquid deposited white flakes; these were 
collected on a filter, and the acid filtrate being evaporated to 
dryness, left a residue, which did not clear on the application 
of a strong heat, and was found to consist of nothing but 2 
MARCET, ON THE FATTY MATTERS 
chloride of sodium. The white precipitate being washed with 
water till the washings ceased to give a precipitate in a solution 
of nitrate of silver, was treated with ether, when it dissolved, 
resuming its crystalline form by spontaneous evaporation; the 
crystals were also soluble in hot alcohol. They fused at 06° C. 
and reappeared at 64° C. When burnt on a platinum spatula, 
this substance charred, ignited, and left no residue. 
In short, there could be no doubt but that it was stearic acid ; 
consequently, it appeared very probable that the original compound 
insoluble in ether was the bistearate or the stearate of soda. The 
fact was placed beyond doubt by a quantitative analysis of the 
substance. For this purpose, a sample of the compound, thoroughly 
exhausted with ether, was dried over sulphuric acid, under the air- 
pump, until it ceased to lose weight; it was then found to weigh 
0275 grammes. The substance was now dissolved in hot water, 
(being insoluble in cold water) and decomposed with hydrochloric 
acid in excess, when an abundant flocculent precipitate of fatty 
acid occurred. The precipitate collected on a filter, and washed 
with distilled water (till the washing ceased to produce a hazi- 
ness in a solution of nitrate of silver), was removed into a 
weighed watch-glass, to be dried over sulphuric acid under the 
air-pump. In order to avoid losing a trace of the fatty acid, 
the filter itself was treated with ether, and the solution evapo- 
rated to dryness in a weighed watch-*glass, which, when dried 
under the air-pump, gave only 0006 grammes of the substance. 
The whole weight of the perfectly dry fatty acid was 0-259; 
therefore, 0-275 grammes of the compound submitted to analysis, 
consisted of 
0-259 grammes of stearic acid, 
and 0’016 grammes of soda. 
0-275 
or, 100 parts contained 
94'18 of stearic acid, 
and 5-82 of soda. 
100-00 
Chevreul found 100 parts of bistearate of soda to consist of 
Stearic acid . . . 94-33 
Soda 5-67 
10000 OF HUMAN EXCREMENTS IN DISEASE. 
3 
Consequently, the substance under examination was bistearate 
of soda. 
It is the first time, I believe, that bistearate of soda has been 
extracted directly from the animal body, and, consequently, in the 
form of an Immediate Principle, Its separation from the other 
fatty acids is very easy, on account of the circumstance that this 
compound is insoluble in ether; and it is readily distinguished 
from the other soaps by its property of crystallising in a concen- 
trated alcoholic solution as soon as the fluid has become cold, whilst 
the other compounds of fatty acid and soda solidify from their 
solution in alcohol, in the form of a gelatinous deposit, which 
crystallises on standing, after some time has elapsed. Bistearate 
of soda was first obtained by Chevreul by dissolving 1 part of 
stearate of soda in 2000 or 3000 parts of hot water, filtering the liquor 
when cold, washing the deposit, drying it and treating it with hot 
alcohol; the solution, when cold, deposited bistearate of soda * 
In no case have I detected this compound as an Immediate 
Principle of healthy human evacuations; it is, consequently, a 
morbid product, resulting, in all probability, from the action of 
abnormally large quantities of free acids in the intestinal canal: 
the very acid reaction of the excrements supports this view. 
Healthy human faeces yield margarate of lime and margarate of 
magnesia; if they contain any soda or potash soap at all, it must 
be in very small quantities. Free fatty acids do not exist in 
healthy human evacuations, unless a comparatively large amount 
of vegetable food has been taken; and in these cases I have not 
detected the presence of any bistearate. 
The excrements in the present instance yielded not only bis- 
tearate of soda, but a considerable quantity of free fatty acids, 
which most probably depended, as I shall presently show, on 
the functions of the pancreas and liver being arrested. 
The alcoholic filtrate from the bistearate of soda, gave on stand- 
ing, another crop of crystals, consisting of a mixture of bistearate 
of soda and of fatty acid. By treating these various deposits with 
ether, a substance was dissolved which crystallised by spontaneous 
evaporation, and proved to be a mixture of stearic and margaric 
acids, the former being in excess. The crystallised deposit pos- 
sessed the following characters. The crystals occurred under the 
form of small white masses, exhibiting under the microscope groups 
* Recherches Chimiques sur les corps gras d’origine animale. Par M. L. Chevreul. 4 
HUMAN EXCREMENTS IN DISEASE. 
of needles radiating from tlie centre to tlie periphery. They fused 
at a temperature of 60°C, which, according to Gottlieb, corre- 
sponds to a mixture of eighteen parts of stearic with ten parts of 
margaric acid; they were soluble in cold ether and in hot alcohol, 
and insoluble in water; the substance dissolved in potash and 
could be precipitated in this alkaline liquor by means of hydro- 
chloric acid; when heated on the platina-knife, the crystals fused, 
ignited, and finally left no residue. These characters are precisely 
those of the above-mentioned fatty acids ; the amount of the mix- 
ture at my disposal did not allow of the complete separation of 
these acids being effected. 
The clear alcoholic fluid being allowed to stand undisturbed for 
twenty-four hours, yielded another crop of beautifully white glis- 
tening crystals. These were submitted to examination and proved 
to be margaric acid, apparently free from stearic acid. These 
crystals dissolved in ether and hot alcohol, and crystallised from 
these solutions; the ethereal and alcoholic fluids had an acid reac- 
tion ; the substance was insoluble in water, but dissolved in aqua 
potassse. Hydrochloric acid induced its precipitation from the 
alkaline liquor. It fused at 53° Cent., and crystallised, on cooling, 
at 49°, this low fusing point being due probably to the admixture 
of a small qiiantity of oleic acid ; the crystals occurred in the form 
of small radiating masses peculiar to margaric acid ; they burnt 
with a fuliginous flame, leaving no trace of ashes. 
The occurrence of such quantities of fatty acids in this case 
being considered in connection with the condition of the body of 
the patient, is of great interest, not only in a chemical but also in 
a physiological and pathological point of view. The pancreas of 
the patient was found, at a post mortem examination, entirely dis- 
organised by malignant disease, and it apparently so compressed 
the duct of the gall bladder that no bile could flow into the intes- 
tines. Consequently, the two alkaline intestinal secretions were 
wanting, and the fatty acids contained in the alimentary canal 
could not be neutralised. This is an important fact in favour 
of Bernard’s view respecting the properties of the pancreatic 
juice. 
I avail myself with pleasure of this opportunity to acknowledge 
tlie valuable aid I have received from my assistant, Dr. Frederick 
Dupre in these and other investigations.