76 REPORT—1840. 
looser in texture than usual, but not otherwise altered in appear- 
ance. When, however, six or eight parts of serum are employed, 
the coagulation is much retarded, the red particles form a dense 
layer at the bottom of the vessel, while the whole fibrin coagu- 
lates alone, forming a voluminous translucent mass,—an artificial 
“buffy coat,” as it would be called by physicians. In this way, how- 
ever, the fibrin is not obtained pure, but has more or less of a red 
tinge, particularly in the lower half of the mass, owing to the red par- 
ticles not having completely subsided before the coagulation took 
place. The results corresponded to what the author had anticipated, 
but he had no expectation of being able to obtain the fibrin perfectly 
pure by filtration, as Miiller had done with respect to the blood of the 
frog. Of the four specimens exhibited by Dr. Buchanan, one consisted 
of the red particles gradually deposited, while the fibrinous coagulum, 
with only a slight tinge of red at its lower part, floated above; the 
other three consisted of fibrin separated by the filter, one of the masses 
floating in serum, the other two in water. These masses are very like 
calf-foot jelly in appearance. They are of a cellular texture, and their 
ellow colour is owing to the serum contained in their meshes, but by 
ablution with water they become of a pure white colour. 
On the Constitution and Products of the Distillation of Fat Bodies. 
By Professor RepTENBACHER and Dr. VARRENTRAPP. 
The object of this paper was to show that the composition of the 
fat acids has hitherto been erroneously stated. A variety of acids were 
subjected to examination, such as stearic, margaric, oleic and sebacic 
acid. Margaric and stearic acids were shown to possess the same radi- 
cal; the former being the higher, the latter the lower oxide of it. This 
radical has the formula of C,, H;3, and may be represented by the 
symbol Ma; thus stearic acid is 2 Ma + 5 O, whilst margaric acid is 
1Ma +30. They thus resemble sulphuric and hyposulphuric acids. 
Margaric acid is one of the products of the distillation of stearic acid ; 
the oxidation of the latter also causes the formation of the former. 
Oleic acid was analysed by these gentlemen, having been obtained in 
a pure state. The results were principally numerical, and are stated 
in Liebig’s Journal for 1840. 
On a New Fat Acid. By Dr. L. Puayrair. 
Dr. Playfair had examined some of the vegetable fats, for the pur- 
pose of ascertaining whether the margaric acid contained in them pos- 
sessed a constant composition. He remarked that the acid in the 
butter of nutmegs was peculiar, and had not formerly been examined. 
Pelouze and Bondet have stated in the Annales de Chimie, that it is — 
margaric acid. Dr, Playfair considered that the radicals of serecic and 
cenanthic acid were similar; in the former, however, one equivalent of 
