i 7 2 SCIENCE PROGRESS 



tive. The theories of physiological units, of the limitation of the size of land 

 animals, and others of less general interest receive careful attention and criticism. 



The exposition of the biological writings of the late Samuel Butler has a 

 peculiar interest of its own. It is a strange fact, with all our professorships and 

 other direct or indirect forms of endowment of research, that so much of the 

 advancement of knowledge, in the things that really matter, is due to outsiders 

 whom the scientific world is careful to ignore. Afterwards they are dragged into 

 the light in a way which they would probably not appreciate. The case of 

 Mendel is, perhaps, not surprising. A modest unassuming monk, who loved his 

 experiments, and neither sought for nor desired recognition, had nothing to gain 

 by self-advertisement. 1 But Samuel Butler was by no means disposed to hide his 

 light under a bushel. And now we find a first-rate biologist telling us that 

 Eretuhon was not his only achievement, but that his biological writings were really 

 scientifically valuable. Dr. Hartog traces his influence in Romanes and others, 

 and is unable to explain why Life and Habit missed its mark. Bergson is not 

 mentioned. The Bergsonian boom had not started when most of these essays 

 were written. But it is interesting to note that the only part of Bergson's evolution- 

 ary theories which have any particular scientific interest or value — Mattel' and 

 Memory— is strangely reminiscent of Samuel Butler's work on unconscious memory. 



There is much else of interest in this collection of essays. The article on 

 nature study should be valuable to teachers. Here, as in other instances, Dr. 

 Hartog is a pronounced opponent of fads. Avoid pseudo-science, is the burden of 

 his remarks. Do not call carbon dioxide chalk stuff gas, and do not teach more 

 than you can help which will have to be unlearned afterwards. The articles 

 reprinted from the Quarterly Journal of Microscopic Science should interest the 

 technical biologist. But the admirable discursiveness, though interesting to the 

 reader, is embarrassing to the reviewer. The book is a distinct addition to the 

 series, and the essays are well worth reprinting in permanent form. 



H. S. Shelton. 



Reduction of Domestic Flies. By Edward Halford Ross, M.R.C.S., L.R.C.P. 

 [Pp. 98, 18 illustrations.] (London : John Murray. Price $s. net.) 



This work emanates from the researches so generously organised by Mr. John 

 Howard McFadden and is written by Mr. E. H. Ross, who was formerly Health 

 Officer of Port Said and is now connected with the researches referred to. The 

 book deals with the whole subject of Domestic Flies chiefly from the sanitary 

 point of view. The author (my brother) is one of the few Englishmen who have 

 conducted large-scale work against insect pests. While at Port Said he com- 

 menced and carried through a campaign of extermination against the mosquitoes 

 which used to abound there in very large numbers — chiefly Stegomyia and Culex. 

 The work was of great difficulty because the town contained a large mixed 

 population of many nationalities and possessed neither sanitary laws nor traditions ; 

 and the result was a very complete and brilliant success— in fact, I think the 

 greatest success which has been obtained in British possessions. Mr. Ross s 

 therefore peculiarly well qualified to speak on the practical reduction of flies, and 

 his book deals with the subject, not only from an entomological point of view, but, 

 what is very different, from the Health Officer's standpoint. 



The method of breeding house flies and proposals for their reduction have 



1 Reference to the Catholic Encyclopedia elucidates the fact that even Mendel was 

 somewhat bitter at the manner in which the scientific world ignored his discoveries. 



