The word Polyethylene was probably first pronounced in a lecture which M. P. E. Berthelot delivered on April ,27, 1863 to the Chemical Society in Paris, reporting on the "polymerization" of various simple organic compounds (1). Much later this work appeared twice in the literature before the classical ICI breakthrough in the 1930's which is so colorfully described in Ballard's lecture. Once it came up at the end of the last century when H. von Pechmann obtained "a white flocculant material" from the decomposition of diazomethane which, one year later, was termed to be "polymethylene" - (CH ) - from E. Bamberger 2 and F. Tschiemer (1). At that time the investigators were disappointed about this product because it was not what they had expected to find in their experiments. As a result any further work was discontinued. The second time that the word polyethylene appeared in the literature to describe a "white solid powder" was in 1930 when C. S. Marvel and M. E. P. Friedericks (2) attempted to prepare alkylated As compounds in which all five valencies were covalently bonded to five monovalent-aTkyl groups. They reacted Tetra-ethyl-arsenium bromide with butyllithium and expected to get tetra ethyl butyl arsenium. Instead they obtained LiBr + AsEt3 + gaseous products. Delicate and somewhat time-consuming analysis gave a surprising result: ethane and C 's were there in the 4 expected quantities but ethylene was missing - or almost missing - in the gas mixture.

The word Polyethylene was probably first pronounced in a lecture which M. P. E. Berthelot delivered on April ,27, 1863 to the Chemical Society in Paris, reporting on the "polymerization" of various simple organic compounds (1). Much later this work appeared twice in the literature before the classical ICI breakthrough in the 1930's which is so colorfully described in Ballard's lecture. Once it came up at the end of the last century when H. von Pechmann obtained "a white flocculant material" from the decomposition of diazomethane which, one year later, was termed to be "polymethylene" - (CH ) - from E. Bamberger 2 and F. Tschiemer (1). At that time the investigators were disappointed about this product because it was not what they had expected to find in their experiments. As a result any further work was discontinued. The second time that the word polyethylene appeared in the literature to describe a "white solid powder" was in 1930 when C. S. Marvel and M. E. P. Friedericks (2) attempted to prepare alkylated As compounds in which all five valencies were covalently bonded to five monovalent-aTkyl groups. They reacted Tetra-ethyl-arsenium bromide with butyllithium and expected to get tetra ethyl butyl arsenium. Instead they obtained LiBr + AsEt3 + gaseous products. Delicate and somewhat time-consuming analysis gave a surprising result: ethane and C 's were there in the 4 expected quantities but ethylene was missing - or almost missing - in the gas mixture.

The clinical examination of common surgical conditions has been paramount in accurate diagnosis and management. This book provides a framework for candidates preparing for the short case clinical component of the surgical examination. It can be used as a companion to other surgical textbooks and a guide for medical students and surgical residents in preparation for clinical work.It includes detailed description of clinical examination steps and techniques, proper presentation of cases, as well as tips and lessons gained from past surgical examinations. The questions and answers in this book are designed according to the Objective Structured Clinical Examination (OSCE) format. They are divided into simple and advanced questions according to difficulty intended at the undergraduate, post-graduate and exit level.The book will be helpful in developing a structure to prepare for the surgical clinical examinations, viva and the OSCE. The illustrations and algorithms included will help the reader grasp concepts of the surgical topic easily and aid the candidate in passing the surgical examinations with confidence.