igi2] William J. Gies 59 



conditions mentioned above. Ferric sulphocyanate readily passes 

 from ether Solution through rubber into ether. 



The writer inaugurated these studies, with Dr. Rosenbloom's 

 Cooperation,^ in the hope of devising improvements in the methods. 

 for the isolation of Hpins. The work is progressing along several 

 lines, especially with reference to methods of isolation and purifi- 

 cation, and to osmosis (see page 64). 



III. A DEMONSTRATION OF OSMOTIC PRESSURE EXERTED 



BY FAT' 



In the first of two demonstrations, a cylindrical rubher bag (Con- 

 dom), 13^ inches in diameter and 8 inches long, was lowered into an 

 oiled miislin bag of aboiit the same dimensions. The rubber bag 

 was then filled to overflowing with olive oil. The rubber bag ex- 

 panded, as the oil filled it, to the füll length and width of the muslin 

 sheath. The sheath prevented further extension of the rubber bag 

 and imparted rigidity to the Osmometer that was ultimately con- 

 structed. The double bag, füll of oil and with its mouth wide open, 

 was then raised so as to inclose about an inch of the lower end of 

 a long glass tube which was firmly supported vertically above the 

 demonstration table. The glass tube was 5 feet long and its bore 

 was 4 mm. in diameter. Ligatures were tightly secured around the 

 neck of the double bag against the immersed lower end of the verti- 

 cal tube. The bag then hung directly from the end of the tube. 

 The bag and its sheath were in a tightly distended condition and a 

 stationary column of oil an inch high in the tube was visible above 

 the protruding edge of the sheath. The tube and bag were then 

 lowered into a salt-mouth liter bottle on the table until the bag 

 almost touched the bottom of the bottle. The height of the bottle 

 and the length of the bag were nearly equal. The tube was then 

 marked with a label on the plane of the oil meniscus just above the 

 neck of the bag, and enough ether was poured into the bottle to pro- 

 vide Immersion for the bag to the depth of an inch. For a mo- 

 ment no change in the volume of oil was apparent, and the lateral 



^Rosenbloom and Gies: Proceedings of the American Society of Biological 

 Chemists, 191 1, ii, p. 8; Journal of Biological Chemistry, 191 1, ix, p. xiv. 



•Rosenbloom and Gies: Proceedings of the Society for Experimental 

 Biology and Mediane, 191 1, viii, p. 71. 



