PROFESSOR GRAHAM ON THE DIFFUSION OF LIQUIDS. 
9 
The following additional ratios of diffusion were obtained from similar solutions at 
a somewhat lower temperature, namely 48° ; — chloride of sodium 100, hydrate of pot- 
ash 151‘93, ammonia (from a 10 per cent, solution, saturated with chloride of sodium 
to increase its density) 70 , alcohol (saturated with chloride of sodium) 75'74, chloride 
of calcium 71'23, acetate of lead 45*46. 
Where two experiments upon the same salt are recorded in the table they are seen 
to correspond to within 1 part in 40, which may be considered as the limit of error in 
the present observations. It will be remarked that the diffusion of cane- and starch- 
sugar is sensibly equal, and double that of gum-arabic. On the other hand, the 
sugars have less than half the diffusibility of chloride of sodium. It is remarkable 
that the specifically lightest and densest solutions, those of the sugars and of sulphate 
of magnesia, approach each other closely in diffusibility. On comparing together, 
however, two substances of similar constitution, such as the two salts, chloride of 
sodium and sulphate of magnesia, that saU appears to be least diffusive of which the 
solution is densest. 
But the most remarkable result is the diffusion of albumen, which is low out of 
all proportion when compared with saline bodies. The solution employed was the 
albumen of the egg, without dilution, but strained through calico and deprived of 
all vesicular matter. As this liquid, with a density of T041, contained only 14*69 
parts of dry matter to 100 of water, the proportion diffused is increased in the 
table to that for 20 parts, to correspond with the other substances. In its natural 
alkaline state the albumen is least diffusive, but when neutralized by acetic acid, a 
slight precipitation takes place and the liquid filters more easily. The albumen is 
now sensibly more diffusive than before. Chloride of sodium appears 20 times more 
diffusible than albumen in the table, but the disparity is really greater; for nearly 
one-half of the matter which diffused consisted of inorganic salts. Indeed the experi- 
ment appears to promise a delicate method of proximate analysis peculiarly adapted 
for animal fluids. The value of this low diffusibility in retaining the serous or albu- 
minous fluids within the blood-vessels at once suggests itself. 
Similar results were obtained with egg albumen diluted and well-beaten with 
1 and 2 volumes of water. The solution diluted with an equal bulk of water, and 
made slightly acid with acetic acid, contained 7^ dry matter to 100 water. Diffused 
from two four-ounce bottles of 1*25 inch aperture, for seven days, at a mean tempe- 
rature of 43°*5 Fahr., it gave products of 1*73 and 1*48 gr., from the evaporation of 
two water-jars, in which cubic crystals of common salt were abundant. The whole 
matter thus diffused in two cells was found to consist of — 
Coagulable albumen 0*94 gr. 
Soluble salts 2*27 gi‘s. 
3*21 grs. 
The diffusion product of the same solution of albumen left alkaline, or without the 
MDCCCL. 
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