8? 
INTERESTING EXPERIMENTS ON THE NATURE OF FIBRIN. 
This led me to suspect that its coagulation 
wiight be owing to some serum still adhering 
to the fibrin ; but the same results were ob- 
tained however carefully the fibrin was wash- 
ed. And, on the other hand, the fibrin, when 
liept in pure water underwent no perceptible 
change, and the water did not extract from 
it any albuminous matter, for it remained per- 
fectly transparent whenboiled. The presence 
of the salt, therefore, is necessary to resolve 
the fibrin into the albuminous matter. 
5. Some of the solution (1) was mixed with 
an aqueous solution of corrosive sublimate. 
No precipitate was produced. I at first sup- 
posed that this indicated a decided difference 
between soluble albumen and the substance 
which the saline solution extracts from fibrin ; 
but, on making the trial, 1 found that a solution 
of white of egg, mixed tvith common salt, is 
not precioitated by corrosive sublimate. This 
fact I now find had been previously noticed, 
6. Some of the same fibrin, prepared from 
human blood, carefully dried at the ordinary 
temperature, and which had been kept in the 
dry state for several weeks, was acted on by 
the solution of salt almost exactly as the recent 
moist fibrin. It swelled, became white, then 
transparent and gelatinous, and in a few hours 
dissolved, leaving a minute quantity of 
whitish matter, which did not cohere like the 
mucus left by the recent fibrin. The solution 
yielded copious coagula when exactly 
like the solution of the recent fibrin . 
7. The solution of common salt emnloyed in 
experiments was dilute, A saturated soV\- 
tion does not appear to have any effect in dis - 
solving fibrin ; but a mixture of equal parts of 
saturated solution and water acts distinctly ; 
and when the saturated solution is diluted 
with four or five times its bulk of water, it 
acts still more rapidly. I have not ascertained 
what degree of dilution produces the most 
effective solutions, but a solution diluted with 
five times its bulk of water, acts more power- 
fully than a stronger solution. 
8. From some trials I am inclined to think 
that by far the greater part of the fibrin dissol- 
ved is coagulated and precipitated by heat. 
When this is deposited the solution still re- 
tains a minute portion of animal matter, 
ai)pai’ently similar to that which is extracted 
from fibrin by boiling it in water. 
9. Solutions of muriate of ammonia, muri- 
ate of lime, muriate of barytes nitrate of 
potash, sulphate of soda, tartrate of potash 
and soda, and acetate of soda, have exactly 
the same effect on the fibrin of human blood, 
that solution of muriate of soda has. They dis- 
solve by far the greater part of th^ fibrin, 
leaving a slight residuum which is either of a 
mucous consistance, or whitish, and without 
cohesion. The solution coagulates about 130° 
Fahr., depositing white flocculi. In like man- 
ner fibrin, if once heated to 130°, is not 
affected by any of these solutions. It is very 
probable that many of the salts which I have 
not tried produce similar effects. Solutions of 
hydriodate of potash, and subborate of soda, 
dissolve the fibrin, but do not coagulate when 
heated. I believe they prevent the coagula- 
tion of ordinary albumen. 
10. The above experiments were made, as 
I have stated, on fibrin of human blood. 
The experiments which I have made on the 
fibrin of ox blood, and sheep blood, have 
given different results. Fibrin from these 
soui'ces does, indeed, yield .some albuminous 
matter to the saline solutions, but it is in 
small quantity. The fibrin retains its cohe- 
sion, and the liquid only yields a slight mud- 
diness, or, at most, a very few flocculi w^hen 
b )iled. The solutions of muriate of ammo- 
nia, common salt, nitre, and sulphate of soda, 
appear to be the most effective. 
U. I have made some experiments on the 
action of some of these solutions, on muscular 
fibre, freed as much as possible from cellular 
membrane, and carefully washed. In no case 
was the muscular fibre completely dissolved, 
or even so much changed as to destroy its 
fibrous appearance, when viewed with the 
microscope ; but, in general, the muscular 
matter was softened, and the liquid gave more 
or less albuminous precipitate when boiled. 
These effects were most distinct with human 
muscle, less so with the muscle of haddock, 
very slight with the muscle of ox, and scarce- 
ly perceptible with the muscle of sheep. 
12. It follows, from these facts, that fibrin 
differs materially in its properties, according 
to the source from which it is derived ; that 
in general it yields to saline solutions, at the 
ordinary temperature, a substance resem- 
bling soluble albumen ; that the proportion of 
this substance yielded by fibrin varies materi- 
ally ; that it is greatest in the fibrin of human 
blood ; that fibrin cannot dissolve in solutions 
of muriate of amonia if heated above 130'"; 
and that several kinds of fibrin are very slight- 
ly acted on by that solution at any tempera- 
ture. 
ON THE SE3QUI SULPHATE OF MAN- 
GANESE. 
By Thoma-s Thomson, M. D., F. R. S., &c., 
Regius Professor of Chemistry in the 
University of Glasgoiv, 
When neutral solutions of sulphate of zinc 
and chloride of manganese are mixed toge- 
ther, no sensible change takes place. But if 
the mixture be concentrated it gradually de- 
posits yellowish-white coloured crusts, which 
constitute a hitherto undescribed salt of 
manganese. 
This salt dissolves readily in water, but I 
could not succeed in obtaining it in crystals. 
Its taste issw'eetish and astringent, and slight- 
ly acid. 
6*26 grs, of it, rendered as dry as possible 
by pressure between the folds of blotting pa- 
per, and subsequent exposure to a gentle heat, 
were dissolved in water and mixed with a 
great excess of carbonate of ammonia. The 
mixture was left for twenty-four hours, and 
dui'ing that time was frequently agitated. It 
was then thrown on a filter, to collect tlie 
white precipitate which had fallen. This preci- 
pitate became brown by exposure to the air, 
and by ignition acquired a reddish tint. In 
