306 



DISCOVERY 



butions to the recently published The Legacy of Greece, 

 together with a new section upon the biology of Aristotle. 

 The whole is a clear, concise, and well-proportioned 

 summary of a big subject. 



The actual achievement of Greek scientific discovery 

 is remarkable, but its yet more important legacy is the 

 scientific attitude of mind, which is characterised by 

 an eager curiosity in the disinterested pursuit of know- 

 ledge and the recognition that careful and accurate 

 observation must furnish the basis of such knowledge. 

 It was these qualities which made Aristotle " one of the 

 very greatest investigators of living nature." 



Until very recent times the scientific reputation of 

 Aristotle has suffered from the results of his vogue in 

 the Middle Ages, which, owing to their theological 

 approach to the great philosopher, neglected some of 

 his best work in favour of his weaker scientific specula- 

 tions. Physiology, for example, he approached with 

 philosophical prepossessions, and did not here make the 

 first-hand investigation of detail the basis of his 

 knowledge. But in natural history the careful accuracy 

 of his observations has been strikingly confirmed by 

 modern science. It was not until the nineteenth century, 

 for instance, that the truth of his descriptions of the 

 sexual processes of cephalopods (molluscs with distinct 

 tentacled heads) or of the embryology of the dog-fish 

 was rediscovered anew. 



Dr. Singer rightly draws attention to the extraordin- 

 arily accurate detail in the representation of animal 

 forms both in Minoan and in early Greek art. Here the 

 artist was the forerunner of the scientist. I can add, 

 from the experience of a prolonged stay in a Greek 

 harbour, a reason for the predilection for forms of marine 

 life which Dr. Singer notices. The crystal clearness of 

 the water makes it possible to study marine life in a way 

 w-hich is impossible off our shores, and the beauty and 

 interest of the scene to be observed by simply looking 

 over the side of a boat is a sufficient incentive whether 

 to artist or scientist. 



Greek medicine and surgery equally displayed the 

 scientific spirit. They broke away from the religious and 

 magical treatment of disease, developed the inductive 

 method of determining its natural causes, and based their 

 precepts upon carefully recorded clinical experience. 



W. R. H.\LLIDAY. 



Practical Plant Biology : a Course of Elementary Lectures 

 on the General Morphology and Physiology of Plants. 

 By Henry H. Dixon, Sc.D., F.R.S. (Longmans, 

 Green & Co.) 



This book embodies the result of many years' teaching 

 experience gained in the School of Botany at Trinity 

 College, Dublin. It consists of a series of thirty lectures 

 designed as " an introductory course in Botany for 

 Medical and other Science students." It is not, as the 

 main title might seem to imply, merely a guide to the 

 practical study of plants, but the practical work schedule 

 at the end of each lecture is an essential feature and 

 enables the student, as far as possible, to test the accuracy 

 of the statements made by the lecturer. Admitting the 



force of the argument that medical students ought to 

 have some acquaintance with botanical science, the 

 difficult question at once arises : " What kind of course 

 is best fitted to their needs ? " Professor Dixon provides 

 the medical student with an introduction to plant biology 

 which is scientifically accurate, conceived on broad lines, 

 and well written. He omits wisely, though one regrets 

 that more attention is not paid to, the methods of 

 response of plants, particularly the higher plants, to 

 external stimuli. The first lecture deals with the use 

 and construction of the microscope ; this is followed by 

 an account of the cell with special reference to the physical 

 properties of protoplasm — the semi-fluid substance com- 

 posed of oxygen, hydrogen, carbon, and nitrogen, which is 

 the basis of life in plants and animals. In the two 

 lectures on the yeast plant the student is introduced to 

 crystalloids and colloids and other subjects of supreme 

 importance. The unicellular plant Chlamydomonas serves 

 as a basis for an account of sexual reproduction and for 

 a lucid explanation of the truth of the statement that 

 green plants not only supply themselves with food 

 materials and energy, but are " actually the purveyors of 

 food and of the energy of the sun to the whole of living 

 matter." The lectures devoted to bacteria rightly 

 emphasise the part played by these organisms in the 

 general economy of plant life. In the lecture on the 

 red seaweed Polysiphonia, a type which some of us 

 would hardly venture to include in a course for beginners, 

 the phenomenon of alternation of generations (i.e. the 

 process by which one generation is produced by asexual 

 spores and the next by sexual cells) is well treated. 

 The alga Volvox serves to illustrate the differentiation of 

 a plant into a mortal body or soma and immortal germ- 

 cells. In the treatment of the higher plants Professor 

 Dixon lays stress on the relation between structure and 

 function and on features of special interest from an 

 evolutionary point of view. The book concludes with two 

 admirable lectures on Heredity and the Theory of 

 Descent. 



There must be many biologists who can recall the 

 impression made upon their minds by the lecturer who 

 first introduced them to the mysteries of the organic 

 world. The first lecture on biology to many students 

 is no ordinary event ; it may initiate the development of 

 a botanist or zoologist, or it may produce an opposite 

 effect. The importance of stimulating the imagination 

 of students on the threshold of a new subject can hardly 

 be overestimated. A clear account of a plant cell, its 

 contents and its work, a judicial statement of facts that 

 have been demonstrated and of problems that await 

 solution, attract the average student and place him in a 

 position to appreciate the meaning of scientific methods 

 and research. It is sometimes asserted that the more 

 difficult and fundamental problems of life are beyond 

 the grasp of the inexperienced, and therefore should not 

 be included in an elementary course, but it is just those 

 problems which produce keenness and stimulate thought ; 

 and, if treated with a due sense of proportion, they have 

 a considerable educational value. Professor Dixon has 

 produced a book which should do much to encourage the 



