Studies from the Rockefeller Institute for Medical Research Volume 43 (Paperback)

This historic book may have numerous typos and missing text. Purchasers can download a free scanned copy of the original book (without typos) from the publisher. Not indexed. Not illustrated. 1922 Excerpt: ... tension in function of the concentration. 4. Prolonged heat, at 55C, and time seem to inhibit this phenomenon. 5. When precipitation occurs in a serum, the bottom of the liquid, which contains the precipitate, has the highest surface tension. When stirred, the surface tension rises a little every time. The upper part, clear, with lower surface tension, shows the reverse phenomenon; after every stirring, the surface tension becomes a little lower. No. 5, pp. 707-735.1 SURFACE TENSION OF SERUM. II. Action Of Time On The Surface Tension Of Serum Solutions. By P. LECOMTE Du NOUY, Sc.d. (From the Laboratories of The Rockefeller Institute for Medical Research.) Plates 58 To 61. (Received for publication, January 11, 1922.) I. INTRODUCTION. It has been shown in a previous paper1 that the surface tension of serum decreased rapidly, as soon as the serum was exposed to the air. This phenomenon is due to the adsorption, in the surface layer, of substances which either travel slowly in the liquid, or are formed in the surface layer, or else to modifications in the arrangements of the group molecules in the surface layer, and possibly to a combination of these causes. In order to study these substances and to obtain an idea of the order of magnitude of their power of lowering the surface tension of water in function of time, it was necessary to measure the surface tension of the same samples of solutions of serum at different intervals, ranging from 2 minutes to 24 hours. Ii. Experimental. 1. Decrease of Surface Tension of Serum Solutions in Function of Time.--Solutions of fresh serum were made in saline solution (NaCl 0.9 per cent). The surface tension of the same layer of liquid was measured by means of du Noiiy's tensiometer, according to the technique previously de...