186 



SCIENCE 



[N. S. Vol. XL VI. No. 1182 



habits of Bacillus mesentericus, whicli, in its 

 various strains, is responsible for ropy bread, 

 are already well known to bacteriologists, and, 

 empirically at least, to all the better informed 

 among practical bakers. There is no reason to 

 doubt that with the increased knowledge now 

 being acquired any outbreaks of rope will in 

 the future be easily controlled. That the pres- 

 ence in the loaf of cereals other than wheat 

 can be directly harmful is most unlikely. A 

 favorable effect should indeed be seen in a 

 somewhat improved balance in the protein 

 supplied. Maize, it is true, is said to be badly 

 tolerated by certain individuals, though such 

 cases must be rare. It is also stated that the 

 starch of maize is not fully gelatinized when 

 it is cooked in admixture with wheat under 

 conditions suitable for the production of an 

 all-wheat loaf. 



These and other points will doubtless receive 

 the attention of the investigating committee. 

 Its most important task, however, will be to 

 decide, by a thorough sifting of the evidence, 

 the more general question as to whether the 

 war bread is, as a matter of fact, producing any 

 iU eilects at all upon the public health. The 

 public will be glad to know that the food con- 

 troller is in possession of the facts. 



Meanwhile, since it is of the utmost impor- 

 tance to the nation that a full supply of bread 

 shall be maintained, while the amount of wheat 

 available is not sufficient for the purpose, we 

 are glad to observe that the medical press is 

 urging the profession to see that the privilege 

 of obtaining high-grade wheat flour for cases 

 supposed to have suifered from the war bread 

 is at any rate not abused. — Nature. 



SCIENTIFIC BOOKS 



The Human Worth of Rigorous Thinking. Es- 

 says and Addresses. By Cassius J. Keyser, 

 Ph.D., LL.D., Adrain Professor of Mathe- 

 matics, Columbia University. The Colum- 

 bia University Press. 1916. Pp. vi -\- 314. 

 Six of the fifteen chapters of this volume ap- 

 peared in Science during recent years,'- while 



1 On page 220 it is stated that Chapter XII., on 

 the "Principia Mathematica, " had been printed 

 in Vol. XXV. of Science. It actually had ap- 



the remaining nine chapters, together with re- 

 prints of some of the six which had first ap- 

 peared in Science, were published in various 

 other periodicals or by the Columbia Univer- 

 sity Press. Hence the volume contains noth- 

 ing new. Its value is due to the convenient 

 form in which these inspiring essays and ad- 

 dresses are here presented. Unfortunately it 

 contains no index and no table of contents be- 

 sides the chapter or essay headings. 



The title of the volume is the same as that 

 of the initial essay, but some of the other es- 

 says contained therein could appropriately 

 have appeared under the same heading, while 

 the remaining ones represent somewhat more 

 special developments along the same general 

 line. Hence the title indicates truthfully the 

 subject-matter of the entire collection. The 

 volume might appropriately have appeared 

 also with the following title: Inspiring 

 thoughts relating to the history, bearing and 

 educational value of mathematics with empha- 

 sis on the philosophical elements. 



The pre-eminent ability of Professor Keyser 

 along the line of presenting the fundamental 

 elements of abstruse subjects in an elegant and 

 popular manner is well known. His style ap- 

 peals perhaps more strongly to non-mathema- 

 ticians than to the majority of the mathema- 

 ticians, who are often so exclusively interested 

 in technical mathematical questions as to be 

 but little concerned with elegance of language 

 and the philosophical question of human 

 worth. Teachers of mathematics should, how- 

 ever, bear in mind that to many of their stu- 

 dents technical mathematical questions have 

 little charm, and that some of these students 

 could doubtless be reached by the more subtle 

 but no less real historical and philosophical 

 questions connected with their subjects. 



Hence the volume before us can be highly 

 recommended for the prospective teachers of 

 mathematics, as well as for those who are in- 

 terested in the general cultural values of vari- 

 ous scientific subjects. The professional 

 mathematician will, however, also find therein 

 much that is presented from a somewhat new 



peared in Vol. XXXV., 1912, and Vol. XXXVII., 

 1913. 



