572 



POPULAR SCIENCE MONTHLY. 



and is one which in the future is destined to 

 receive more and more attention. We come 

 next to the consideration of papers and of 

 paper-setting. It is the fasliion to hold that 

 any one who knows his subject can examine 

 in it, but in truth it is not so, and the art of 

 examining is one which, like other arts, needs 

 to be learned. It is impossible to deny that 

 many examination papers are ill expressed, 

 and some wholly unsuitable. It is no legiti- 

 mate part of an examination to take the 

 candidate by surprise, or confound him with 

 the .unexpected. Nor should half of the time 

 allowed be taken up in the effort to under- 

 stand what the terms of the question are in- 

 tended to mean. . . . Modern education, in 

 its zeal to avoid the charge of being super- 

 ficial, incurs, as it seems to me, that of being 

 merely fragmentary. It aims at thorough- 

 ness, but is obliged at once to admit that it 

 can attain it only in certain subjects which, 

 compared with the sum of human knowledge, 

 are but few and small. . . . Excepting a 

 very few of us, we are all mere smatterers 

 as regards almost all that we think we know. 

 It is not possible to be otherwise, excepting 

 at the cost of being wholly ignorant in many 

 directions ; and as regards fitness for the af- 

 fairs of hfe, better by far a general acquaint- 

 ance with all that is around us, though it be 

 not very deep, than slices of profound knowl- 

 edge placed sandwichwise between thick lay- 

 ers of utter ignorance." 



Hygiene of OysterSt Prof. Herdman and 

 Prof. Bryce have found, from experiments 

 on the effect upon oysters of various condi- 

 tions with especial reference to the typhoid 

 germ that beneficial results are derived 

 from aeration, and therefore that it is salu- 

 tary to lay the moUusks down where there is 

 a good change of water. Of foods given to 

 oysters, sugar caused them to lose weight 

 and die ; oatmeal and flour had like effects. 

 Stagnation was deleterious, causing the ac- 

 cumulation of excretory products, and encour- 

 aging the growth of micro-organisms and the 

 formation of scums on the surface of the 

 water ; yet the oysters were tolerant of sew- 

 age, and could, up to a certain point, render 

 water clear that was contaminated with it, 

 and they -could live a long time in water 

 rendered opaque by fecal matter. The fecal 

 matter from typhoid subjects was more in- 



imical than that obtained from healthy ones. 

 The oysters were found very prone to infec- 

 tion by micro-organisms, but the typhoid 

 bacillus will not flourish in clean sea-water ; 

 and the experiments seem to show that this 

 organism decreases in numbers in passing 

 through the alimentary canal of the oyster. 

 It seems possible, therefore, that by methods 

 similar to those employed in the clearing 

 basins of the French ostreoculturists oj'Sters 

 previously contaminated with sewage can be 

 freed from pathogenic organisms or their 

 products without being spoiled for the mar- 

 ket. 



Bibliography of Zoology. The Interna- 

 tional Bibliographical Bureau for Zoology, 

 the organization of which was begun about 

 three years ago, will be located, Mr. H. H. 

 Field announces, at Zurich, Switzerland. It 

 will publish a fortnightly bibliographical Bul- 

 letin, with an edition printed on thin paper 

 and on only one side of the sheet, so that it 

 may be cut up ; and a complete card cata- 

 logue of all zoological literature published 

 after 1895; besides which the Zoologische 

 Jahresbericht will be federated with the un- 

 dertaking, so as to afford an annual list of 

 titles, arranged alphabetically, by authors. 

 The bureau will be aided in various parts 

 of the world by national committees, corre- 

 spondents, and sub-bureaus. 



Engineering as an Exact Science. So 



far as it is based on mathematics, said Mr. 

 L. F. Vernon Harcourt in the British Asso- 

 ciation, engineering is an exact science, and 

 the strains due to given loads on a structure 

 can be accurately determined; but the 

 strength of the materials employed has to 

 be ascertained before any structure can be 

 properly designed. Accordingly, the resist- 

 ance of materials to tension, compression, 

 and flexure has to be tested and their limit 

 of elasticity and breaking weight to be de- 

 termined. Numberless experiments have 

 been made on the flow of water in open 

 channels, over weirs, through orifices, and 

 along pipes, and the influences of the nature 

 of the bed, the slope, depth, and size of the 

 channel have been investigated. Electrical 

 engineering is especially adapted for experi- 

 mental investigation, but every branch of 

 engineering science is more or less capable 



