d, which can only receive limited quantities of water, as ¢.7. 
uulo-e, are, when brought into contact with water, soon saturated, 
and have thereafter an unvarying attraction for water. When, 
refere, an arabin or albumen solution of certain concentration 
eives no water through the animal bladder or parchment, this 
ily shows that with the concentration given, these colloids have 
ss attraction for water than the membranes have. If, how- 
eyer, the concentration is raised above a certain limit, the attrac- 
' tion of the membrane for water is overcome, and endosmose 
occurs. This limit, the same membrane being used for different 
colloids, must evidently depend on the attraction of these for 
water. My experiments show that in equally concentrated solu- 
_ tions tannin gives the greatest endosmotic action; then follows 
—arnbin, and next albumen, an order agreeing with the stability of 
these substances in their aqueous solutions, which may in general 
e taken as a measure of their affinity for water. From mem- 
branes like pyroxilin, in which the water is held with little force, 
_ it can be withdrawn by weak colloid solutions; hence a much 
" greater endosmotic effect is seen in this case. 
In further support of the explanation now given, we have the 
fact that with membranous substances chemically the same the 
oid solutions show greater endosmotic force the less dense 
1e membrane is, 7.c. the wider its water-filled interstices are. In- 
d the attraction of water to the substance of the membrane 
must diminsh greatly with the distance. 
__ The particles of water in the central parts of the interstices will 
be less attracted the wider these interstices. This may be illus- 
trated by using two pyroxilin membranes of different densities, 
Thus, employing a 7 per cent. arabin solution, it was found that 
in 24 hours 5*3.cc. water passed through the denser membrane, 
thereas 9°5 cc. passed through the other. Similarly with 
two pieces of parchment from different manufacturers, a 10 per 
cent. arabin solution gave in one case 0°5 cc., and the other 
*6 cc. endosmose, and after expanding in all directions, the more 
compact of the two, an equally concentrated arabin solution, 
save, with it, 3°5 cc. endosmose. 
__ If we consider the case of the impure colloids, it is not easy to 
‘see in what way the presence of so small a quantity of crystalloid 
substance increases the endosmotic action so greatly; for the same 
J quantity of crystalloid, taken by itself, does not give the weakest 
perceptible endosmose. In the converse case, addition of a 
‘small quantity of colloid toa crystalloid solution, the endosmose 
of the latter is increased also. 
_ Fick observed that endosmotic equivalents must be higher the 
re mobile the particles of the salt solution employed. The 
sence of colloids in the solutions makes the latter denser ; 
en, however, a crystalline substance is dissolved in a dense 
- fluid, its particles must be less mobile than in solution with pure 
water; and this is the most probable explanation of the action of 
colloids in exalting the endosmotic force of crystalloid sub- 
_ stances. 
It is, however, found that when a colloid solution is submitted 
to diosmose of water containing even a small quantity of a crys- 
talline salt, instead of to pure water, the endosmose of the colloid 
is considerably diminished. 
The action of the crystalloid in this case cannot be attributed to 
in endosmotic current originated by it ; none of the salt solu- 
ons that were employed showed, in direct experiment with 
water, the slightest increase of volume at the cost of the water. 
_ The phenomenon is one requiring further experiment in order to 
| oe at its explanation. A. B. M. 
e 
i 
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fa 
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SCIENTIFIC SERIALS 
 Poggendorff’s Annalen der Physik und Chemie, No. to, 
1872.—This number commences with a paper by Dr. Herwig on 
the expansion relations of superheated vapours. In his experi- 
ments he used a U-tube, one limb of which contained the vapour 
and the other dry air, these being separated by a little mercury, 
and the instrument being heated in a bath. The general result 
arrived at is that, at certain low pressures, with constant volume, 
superheated vapour has a smaller coefficient of expansion than 
that of perfect gases (viz. 0°003663). The numerical results for 
sulphide of carbon, chloroform, and alcohol, are tabulated.—J. 
Baranetzky communicates a long and interesting paper of re- 
‘searches in diosmosis.* Sketching the history of the subject, he 
points out several defects in previous investigations. Nearly all 
* See ante, p. 152. 
biel) 
the experimenters from Vierodt’s time have sought to determine 
the endosmotic equivalents of salts, and the results are very dis- 
cordant. The diosmotic properties of colloids have been imper- 
fectly studied and misconceived. The membranes employed 
have mostly been animal, and the influence of the nature of the 
membrane is a question which, M. Baranetsky thinks, has haidJy 
been touched. Having directed his experiments to some of these 
points, he shows the influence of various kinds of membrane 
(parchment, bladder, artificial cellulose, pyroxilin), and various 
thicknesses of membrane on the endosmose of various salts. As 
to the colloids, he found that, when of moderate concentration 
(say 10 p. c.) and freed from mineral substances, they showed 
little or no endosmose ; and for the same degree of concentra- 
tion, pyroxilin and cellulose gave more endosmose than animal 
membranes. The writer further discusses the influence of adhe- 
sion, and concludes by applying his observations to animal and 
plant life—G. Vom Rath gives his concluding mineralogical 
paper, treating chiefly of the chemical composition of some 
Vesuvian products ; and this is followed by an account of some 
studies in micro-mineralogy (last of a series also) by Dr. V. 
Lasaulx.— In a note by EI. F. Weber, on the specific heat of 
carbon. the discrepancy of various observations is attributed to 
the fact that the specific heat (in this case) varies with the tem- 
perature, being tripled, in the case of the diamond, between 0° 
and 200°. 
THE Zens for July 1872, contains—“ Algze Rhodiaces, a list of 
Rhode Island Algze,” by Stephen T. Olney, including the Desmi- 
diaceze and Diatomaceze.—‘‘ The Cell,” by J. N. Danforth, M.D., 
commences an examination of the theories of cell development. — 
“ The Flora of Chicago and its vicinity,” hy H. H. Babcock, is 
continued from the previous numbers.—‘‘ The Markings of 
the Test Podura Scale,” by F. W. S. Arnold, M.D,, 
accompanied by an Albert-type plate from negatives produced 
by the author. It contributes very little to the controversy, 
‘* A Conspectus of the Families and Genera of the Diatomacez,” 
by Prof. H. L. Smith, is continued, with an ‘‘ Index to Synonym 
Register.”—‘‘ Microscopical Memoranda for the use of Practi- 
tioners of Medicine,” by Dr. J. J. Woodward, is also continued 
from the previous number.—‘‘ Fungi in Cows’ Milk,” by Prof. 
James Law. In this case the fungi are presumed to have 
originated from impure water supplied to the herd.—‘‘ Hepa- 
tica,” by H. H. Babcock, and ‘*Puccinea on Paper,” by 
Thomas Taylor, are short papers ; as are also those by F. W. S. 
Arnold, on ‘‘ Hematoxylin as a staining material for animal 
tissues ;” and A, Prazmowski, on ‘‘ Draw-tubes v. deep eye- 
Pieces.” 
In No. 1 of the Proceedings of the Swedish Academy of Sciences 
for the present year (Ofversigt af Kongl, Vetenskaps Akademiens 
Forhandlingar, Arg. 29, No.1) M. A. E. Férnebohm givesa geog- 
nosticsection of the central chain of Scandinavia between Ostersund 
on the eastand Levanger on the west. The section includes primi- 
tive Cambrian and Silurian rocks, and the author remarks that 
the most striking point in it is, that fossiliferous Silurian rocks 
are covered in the Areskuta by two great schistose non-fossilife- 
rous formations resembling the typical rocks of what he calls the 
primitive formation (gneiss, hornblende, schists, &c.). A short 
summary in French is appended to this paper, which is illustrated 
with woodcuts and a folding plate.—M. E. Edlund communicates 
a continuation of his attempt to explain the phenomena of elec- 
tricity by means of the luminiferous ether.—From M. O. J. 
Fahrceus we have a long series of Latin descriptions of Caffrarian 
Longicorn Coleoptera collected between the years 1838 and 1845 
by J. A., Wahlberg. The species here described (58 in number) 
belong to the divisions Prionzde and Cerambycide, and include the 
types of several new genera.—M. H. Gyldén gives formule and 
tables for the calculation of the distance at which lighthouses 
may be visible.-—-M. Hjalmar Stolpe communicates the results of 
natural history and archzeological investigations in Bjérko and 
Malaren.—The tendency of the trichomata of plants to changes 
of form is the subject of a paper by M. P. G. E. Theorin, in 
which the author describes and figures certain forms of those 
organs occurring in the common yellow water-lily.—M. Gustaf 
Eisen notices some Arctic oligochzetous annelides, including 
three species of Zumbricus and a Rhynchelmis from Newfound- 
land, and a Lumbriculus from Greenland. Lumébricus puter 
(Hoffm.) is briefly described, and Luchytraus Pagenstecheri 
(Ratzel) from Greenland, in more detail, for comparison with a 
new species, Z. Radze/i, from the northern parts of Norway. 
Figures are given of the characteristic parts of the last two 
species. 
