( 540 ) 
have tried whether it is admissible to add some soft organs, spleen 
or liver to the blood. With the blood of three specimens of a fresh- 
water fish from Surinam, Mrythrinus unitaeniatus, Spix, the same 
freezing point was found twice with the bulb of the thermometer 
not quite immersed, — 0.577°; then the livers of two specimens 
were added and — 0.60° was found. So improvement must not be 
sought in this direction'). With the rabbit still more considerable 
differences were obtained, probably on account of the conversion of 
glycogen into glycose. 
The determinations were made with an in many respects modified 
BECKMANN apparatus, of which the description will be given later. 
Here it may suffice to remark that if a supercooling of 0.5° is used 
as well for the determination of the zero point as of the freezing 
point, the figures obtained for pure salt solutions are very accurate. 
For 1 °/, NaCl (4 gram NaCl dissolved in 100 grams of water, the 
weights reduced to a vacuum) the apparatus gives — 0°.589, the 
result of the ““Präzisionskryoskopie” (HAMBURGER |. e. pag. 96). 
BECKMANN’s correction for increase of concentration with supercooling 
a al 
was always applied, amounting for 0.5 to 160 Or 50=05 (80 
calories being the latent heat of melting ice). The temperature of 
the cooling bath was — 2°.5, when necessary it was lowered to 
— 2°.9 by strong stirring. 
We will first deal with the results obtained with freshwater 
animals. Let A be the freezing point in degrees centigrade, omitting 
the — sign. 
Freshwater bony fishes. 
L 
Perch, Perca fluviatilis L. ae 2 and 5 specimens from Utrecht. 
Remark. The perch occurs in the whole Baltic sea as far as the Sound, Le. 
in water containing to 12°/o, salt and with A = 0.64. 
0.527 _ 1 spec. from Bergen. 
Carp, Cyprinus carpio L. E 1 » the Amsterdam Aqua- 
Cee 0.540 rium, lived in water of A =0,039. 
Remark. The carp seldom penetrates into the Baltic sea, oftener into the Asow 
and Caspian seas. 
0.466 ) 1 resp. 3 spec. from Utrecht, 
Tench, Tinca vulgaris Cuv. caught healthy in October and 
0.514 ) kept some time in the caufs. 
Remark. The tench goes from the Haffs and bays as far as Gothland, where 
A is about 0.42. 
1) By reducing the size of the freezing tube and by using a smaller BreckMAnn’s 
thermometer of an old pattern, the quantity required can be reduced to 5 or 6 ce. 
By means of salt-solutions it will be controlled how far the results need correction. 
