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Journal ArticleDOI

Palmar ridge systems

01 Jun 1987-International Journal of Anthropology (Kluwer Academic Publishers)-Vol. 2, Iss: 2, pp 97-104
TL;DR: In this paper, a six or seven-fingers "sites" system with sequential invasion of interdigital ridge bundles is proposed, where the palmridges of the left hand lag one "period" behind those of the right hands.
Abstract: A six — or seven — (fingers) «sites» system with sequential invading of interdigital ridge bundles agrees very well with actual data from literature. The palmridges of the left hand lag one «period» behind those of the right hands. Main line formulas and the regularities in their frequencies are to a large extent predictable and can be understood from the 7- «sites» model proposed in this publication.
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Book
01 Jan 1961
TL;DR: This book is indispensable for the dermatologist and for any pathologist dealing with dermatological material, and the provision of reasonably full and up-to-date lists of references following each chapter is the greatest merits.
Abstract: WALTER J. LEVER, M.D. Third edition. Pp. vii + 653 with 320 illustrations. London: Pitman Medical. Philadelphia: J. B. Myincott. I96i. C6. It seems almost presumptuous for a dermatologist to review the new edition of Lever's book, so used is one to its being an authoritative guide in the histopathology of the skin. Here is Lever in an up-to-date, more valuable form, preserving intact the virtues of the earlier editions. The general classification used by the author is under the headings of congenital, non-infectious vesicular and bullous diseases, non-infectious inflammatory diseases, drug eruptions, degenerative diseases, diseases caused by bacteria, fungi, protozoa and viruses, metabolic diseases, tumours and the lymphoma and myelosis group. It is, therefore, easy to follow and explore. In this third edition, seven years after the second, much has been rewritten. Emphasis is laid on the developing techniques of histochemistry and electron microscopy. Several newly recognized entities of great interest to dermatologists-e.g. sub-corneal pustulosis and kerato-acanthoma-have now been assimilated into the book. A few diseases previously recognized but not discussed by Lever have now been included, e.g. lethal midline granuloma of the face. There is, as before, an abundance of good black and white photographs, but the text is perhaps more important, providing a clear dissertation on the histological features of every feature under discussion, with brief notes on the clinical appearance; the attention paid to differential (histological) diagnosis is especially valuable. Unobtrusively the reader is given an account in which fact and theory, experimental and clinical findings are given their due share. The style is of consistent clarity. There are excellent introductory chapters on techniques, embryology and the histology of normal skin. The book is rounded off by a useful glossary and a good index. One of the greatest merits of this book is the provision of reasonably full and up-to-date lists of references following each chapter; lists which are not narrowly confined to American sources but which draw upon the dermatological Jiterature of the world. This book, the new edition no less than the old, is indispensable for the dermatologist and for any pathologist dealing with dermatological material.

493 citations

Journal ArticleDOI
TL;DR: Topology is a branch of mathematics, concerned with the study of properties which are unchanged by continuous deformations, whereas a solid sphere and a solid cube are topologically indistinguishable from one another whereas asolid sphere, a ring, and a hollow sphere are all topologically distinct.
Abstract: Topology is a branch of mathematics, concerned with the study of properties which are unchanged by continuous deformations. The geometrical concepts of ‘size’ or of precise ‘shape’ are not relevant to topology. If an object is distorted continuously without being torn apart or glued together, then its topology does not change, even though its precise geometrical configuration may become drastically altered. Thus, a solid sphere and a solid cube are topologically indistinguishable from one another whereas a solid sphere, a ring, and a hollow sphere are all topologically distinct. A topological classification of ridge patterns, therefore, will take no account of the normal geometrical relations such as ‘distance’ or ‘angle’. We may imagine the ridge patterns to be drawn on a rubber glove. The glove may be stretched or distorted in any way whatsoever (provided it is not torn or glued) and the topology of the patterns will not change. But it is dear that distance and angle measurements may be drastically altered by such deformations. In Fig. 1 , the circle (a) and the winding line ( b ) are topologically identical, whereas the open curve (c), although geometrically much more like a circle than ( b ) , is topologically distinct from (u,). I n many ways, a topological classification must be regarded as a rather crude one, since it ignores so much of the geometry. However, there are certain contexts in which topological ideas can prove very useful indeed. The subject has, in fact, been a very fruitful and actively studied one in modern mathematics. It also has applications in the physical sciences sometimes of a rather unexpected character. Perhaps it is less surprising that applications in the biological sciences are to be found in some areas. When a living thing grows, it is to be expected that considerable changes in size and shape may take place continuously, whereas changes in the topological structure might be imagined to occur only a t very special times in its development. In addition t o purely topological matters, there is another consideration that I feel may be important for classification schemes in biological contexts. This is the question of the stability of a classification. I n Fig. 2 is an illustration of what is an unstable situation, if we are concerned with the entire topological pattern of lines. It will be noticed that the two patterns are topologically quite distinct from one another, since the left-hand pattern contains several closed loops, whereas that on the right consists entirely of two open strands. However, only a very small locul distortion is needed in order to pass from the left-hand pattern to the right-hand one, namely a shunt upwards by one ridge of the portion to the right of the broken line. Any classification scheme which depends on tracing the connectivity of the entire pattern of lines is likely to be unstable in this sense. If the laying down of ridge patterns in a developing embryo is governed by purely local criteria, then the two patterns illustrated in Fig. 2 would have to be judged as being basically similar, even though they are topologically very different from one another. (If such differences in global pattern are to be found, for example, between identical twins even when the local pattern configurations are similar, then this could be viewed as lending support t o a hypothesis that the laying down of the ridges is indeed a Iocal process.)

44 citations