Book Reviews and Notes

n/

THE NATIVE PROTEIN THEORY OF THE STRUCTURE OF CYTOPLASM

I have selected cytoplasm as the subject of my contribution to this symposium for various reasons. (1) The cytoplasm has aptly been called the substratum of life (Frey-Wyssling, 1940) since it is the medium in which many of the processes of living matter take place. Its study is therefore of the first importance for physiology and biology in general, and for cytogenetics in particular, and as such merits a place in our deliberations. (2) There now seems to be a consensus of opinion that the essential characteristic of cytoplasm is its structure. Thus it is reasonable to hope that the policy of applying to biological materials the newer knowl-edge of structure chemistry against a background of classical and modem geometrical concepts (Wrinch, 1934, 1936) may yield results in this new field. (3) The cytoplasm contains, in addition to a very large amount of water and certain other sub-stances, such as carbohydrates, fats and salts, some native protein. A fairly complete picture of the nature and characteristics of native proteins has been obtained in recent years from studies in phys-ical chemistry, crystallography and enzyme and immunochemistry. It would, therefore, seem of interest, and even of urgent importance, to consider the problems of cytoplasmic structures in the light of this newer knowledge. This seems necessary espe-cially in view of the fact that recent discussions have uniformly adopted as axiomatic the older picture of protein structure, antedating Svedberg's work and based upon nothing more relevant than certain ideas derived from studies of silk, wool, feather quill, nail, scales, spines, horn, tendons and car-tilage, proteins which appear to play little part in the essential life processes. In the cytoplasm, if anywhere, the proteins must be presumed to be in their native state

On the Pressure Distribution Round Certain Aerofoils of High Aspect Ratio

The development of aerodynamical research into the usefulness of wing profiles of various types for aerofoils of high aspect ratio lends special interest to new results in two-dimensional hydrodynamics relating to the motion of a perfect fluid in the presence of a cylindrical body, especially in the case when the curve of cross-section of the body possesses only a smali amount of camber and is cusped at one end and rounded at the other.The possibility of formulating a theory which represents with reasonable accuracy the actual motions of aerofoils of high aspect ratio in a stream of air, when the air it taken to be inviscid, depends, of course, essentially in the first place on finding motions in which there is a force on the body at right angles to the direction of streaming. No theory which omits to produce this lifting force can give an account of the actual motions of aerofoils which is even approximately satisfactory.</jats:p