Number of contr. 
yer min. 
sit 
per min. 
Number of contr. 
4 
pe a o-—— Wat 
25 { - -— To eg TAI 
een ea ae 
eenn, 
Hi NPD 0 4 
0.6 4.2 ‘ = 18 0.6 1.2 vin hd or 18 
Osm. druk = Osm. pressure. Osm. druk = Osm. pressure. 
Diagram VII. Diagram VIII. 
Effect of an increased osmotic pressure on the Effect of an increased osmotic pressure on the 
frequency of the sinus venosus with urea. — frequency of the sinus venosus wilh canesugar. 
Osmotic pressure expressed in °/, NaCl. Osmotic pressure expressed in ®/, NaCl. 
mitted the same sinus successively to the action of cane-sugar and 
urea (N°. 28) and again we obtained the same result. 
Now it may be looked upon as certain that cane-sugar will be 
osmotically active as regards the muscular fibres of the sinus. 
The fact that urea shows so little activity in such a strong con- 
centration, thus differing so much from a substance possessing osmotic 
activity suggests the conclusion that the muscle fibres of the sinus 
are permeable CO(NH,),. If this is the case, an addition of uvea 
must cause a withdrawal of water — and consequently a smaller 
Number 29; 24—3—16; t = 14°; 10.50 h. R. esculenta; sinus venosus perfused. 
Cut through both aortae and both venae cavae sup. 
The experiment was continued at 25-3-16 and summarised as follows: 
‚Number of contr. | Osmotic 
Letter on Time Fluid per 1’ after rd Remdtke 
the curve in 0/o 
. 5/ 10’ | Nac 
{ | before | 
| | the | 
hy | 11.30 | RINGER exp. 23 0.6 t= AG" 
M’N’ 11.33 | RINGER + urea 21 Bas TES 
Q' P’ 11.47 | RINGER--urea | 23 oe WES 
OER 11.58 | RINGER 26 25 0.6 
