July lo, 1890] 



NATURE 



245 



dition of the people. A number of pages are taken up 

 -ivith a description of an ideal water-supply and methods 

 of drainage, great stress being laid on the necessity for 

 laying down drains and sewers of the smallest possible 

 size consistent with the immediate removal of the maxi- 

 mum flow at any one time. The wisdom of such a plan 

 is now admitted on all hands, the powerful flow prevent- 

 ing all deposit, and by maintaining a down draught from 

 the houses, avoiding the ingress of sewer-gas. 



In the section on " Health in the School," we find an 

 account of the " Half-time System " initiated by Sir E. 

 Chadwick with the object of ensuring to children em- 

 ployed in manufactories a certain time for school-work 

 and recreation, in addition to that devoted to physical 

 labour. The time which should be occupied by lessons 

 at various ages, and the effect of good lighting, warming, 

 ventilation, and personal cleanliness in augmenting the 

 receptivity of pupils, are ably discussed, and the value of 

 military drill as a part of the education is rightly insisted 

 on. The methods for the prevention of the occurrence 

 and spread of epidemics are so briefly touched upon, 

 that we cannot but think that the importance of the 

 subject might have demanded somewhat fuller treat- 

 ment. 



The most important portion of the following section 

 deals with the results of occupation and surroundings on 

 the length of life in various classes of society, the effects 

 of intemperance and of bad feeding being specially con- 

 sidered ; the author, however, being careful to point out 

 the sources of fallacy to which all such statistics are 

 liable. The last portion of the book is mainly devoted 

 to an attack on the Malthusian theory. 



The work is not, and does not in any way pretend to 

 be, a student's text-book, so that the candidate for a 

 diploma in public health will hardly find it of much 

 value, except, perhaps, from an historical point of view. 

 Still, there is much in its pages which may be studied 

 with advantage by those interested in matters pertaining 

 to general hygiene, especially as it presents in moderate 

 compass a most readable account of the labours of a 

 distinguished pioneer in the field of sanitary science. 



OUR BOOK SHELF. 

 Induction and Deduction, and other Essays. By Con- 

 stance C. W. Naden. Edited by R. Lewins, M.D. 

 ( London : Bickers and Son, 1890.) 



This little work acquires a melancholy interest from the 

 fii t that the talented young authoress has not lived to 

 see its publication. The title essay, on " Induction and 

 Deduction," gained in 1887 the Heslop Memorial 

 Medal, provided out of the proceeds of a bequest to the 

 Mason Science College of Birmingham by the late Dr. 

 Heslop, and awarded annually by the Council of the 

 College. It is clear, concise, well-arranged, and carefully 

 thought out ; and leads one to believe that, had the hand 

 of Death been withheld, Miss Naden would have made 

 \ a' uable contributions to philosophic thought. For Miss 

 -Xaden the fundamental principle in philosophy is the 

 f imous Protagorean formula of relativity, that " Man is 

 the measure of all things, of things that are that they are, 

 of things that are not that they are not." She insists on 

 tlic close inter-connection of induction and deduction in 

 all reasoning, the two processes not being antagonistic 

 but complementary. Both involve cognition and recog- 

 nition ; but whereas induction is a process of cognition 

 involving recognitions, deduction is a process of recogni- 



NO. 1080, VOL. 42] 



tion involving cognitions. The historical development is 

 traced from the Greek cosmologists, through Plato, Aris- 

 totle, Bacon, Descartes and Locke, Mill, jevons, and J. 

 H. Green ; and there are many signs that Miss Naden 

 had not merely grasped but assimilated the teachings of 

 those whose influence on the theory of reasoning she 

 traced. 



That Miss Naden was not wanting in humour is seen 

 from the " Legend of the Inductive Method " in her 

 introduction. This is so good as to be worth quoting. 



" In the beginning was a set of philosophers, who, 

 instead of looking about them, simply investigated their 

 own thoughts, and tumbled into many ditches, not so 

 much through star-gazing, as through mind-gazing. Out 

 of their inner consciousness they extracted a great many 

 principles which were inapplicable to Nature, and were 

 therefore of none effect ; and on account of this wilful 

 perversion they failed to invent the steam-engine or to 

 discover the circulation of the blood. This state of 

 things went on for a long time ; and in the Middle Ages 

 matters grew worse rather than better ; for now there 

 appeared a set of men called schoolmen, who submitted, 

 everything to the authority of the Church and of Aristotle, 

 and wasted their time in frivolous debates about phan- 

 toms named quiddities and hocceities and haeceities. 

 Their method also was deductive, and was false. But in 

 the glorious sixteenth century, and in our own glorious 

 island, there arose a Lord Chancellor who wrote a book 

 which changed the face of the intellectual world. This 

 great man found out that the proper office of the mind is 

 to make discoveries, and that the proper way to make 

 discoveries is to interrogate Nature. He laid down rules 

 for the correct framing of our interrogations. He is the 

 father of all such as make far places near by steam- 

 engines and electric telegraphs, or numb our pain by 

 anaesthetics, or light the world by gas or electricity. His 

 method is called inductive, and is true." 



The other essays are on ethical and sociological ques- 

 tions, and on " Hylo-Idealism : the Creed of the Coming 

 Day." They are somewhat unequal in value. The work 

 is prefaced by a short memoir. . C. Ll. M. 



The Lepidopterotcs Fauna of Lancashire and Cheshire. 



By John W. Ellis, M.B. (Vic), F.E.S. (Leeds : Printed 



by McCorquodale and Co., 1890.) 

 This volume, the contents of which are reprinted from 

 the Naturalist, will be of great service to all students of the 

 subject to which it relates. Dr. Ellis does not offer his 

 hst as conclusive ; but he has " endeavoured to present, 

 as completely as possible, the facts known with reference 

 to the occurence in Lancashire and Cheshire of the 

 British species of Lepidoptera." The list is preceded by 

 a short statement as to the geological and meteorological 

 conditions which, by affecting the flora of the district, 

 affect indirectly its lepidopterous fauna. 



LETTERS TO THE EDITOR. 



[ The Editor does not hold himself responsible for opinions ex- 

 pressed by his correspondents. Neither can he undertake 

 to return, or to correspond with the writers of, rejected 

 manuscripts intended for this or any other part of Nature. 

 No notice is taken of anonymous communications. '\ 



Intelligence of Chimpanzees. 



One is glad to see that your review of Mr. Stanley's book 

 calls attention to the following statement, which is made on the 

 authority of Emin Pasha, and rendered in his own words : — 



" The forest of Msongmais infested with a large tribe of chim- 

 panzees, In summer-time, at night, they frequently visit the 

 plantations of Mswa Station to steal the fruit. But what is re- 

 markable about this is the fact that they use torches to light the 

 way ! Had I not witnessed this extraordinary spectacle per- 

 sonally, I should never have credited that any of the Simians 

 understood the art of making fire." 



On this passage your reviewer remarks : — " We cannot doubt 



