838 



SCIENCE 



[N. S. Vol. XXXVII. No. 961 



not present in the non-pregnant individual. 

 If now the serum or plasma of a pregnant 

 woman is added to peptone prepared from 

 human placental tissue and the mixture ob- 

 served by the optical method, the initial rota- 

 tion changes, while with serum from a non- 

 pregnant woman, the initial rotation remains 

 unaltered. As this phenomenon could be de- 

 tected as early as the first month of preg- 

 nancy, the procedure promises to be of great 

 value in the difPerential diagnosis between 

 extra-uterine pregnancy and tumors of the 

 adnexa. It may, perhaps, be added that this 

 ingenious method apparently does not remove 

 all the dilBculties and doubts which surround 

 the early diagnosis of pregnancy, for recent 

 investigations seem to show that a positive re- 

 action may also be obtained under other con- 

 ditions than pregnancy. 



The booklet may be recommended as a very 

 readable, stimulating summary of a large 

 number of investigations by Abderhalden and 

 his pupils. 



J. AUER 



Rockefeller Institute 



Methods for Sugar Analysis and Allied Deter- 

 minations. By Arthur Given, B.S. Phil- 

 adelphia, P. Blakiston's Son & Co. 1912. 

 Pp. Y5. Price $2.00 net. 

 According to the preface, this book has been 

 made, because, as the result of ten years' 

 experience, the author has found that " it has 

 become increasingly evident that the present 

 methods as given in many of the books on 

 sugar analysis and in the A. O. A. C. methods 

 are not sufficiently explicit as to the proper 

 method for a particular case, thereby con- 

 fusing the novice, and making it difficult to 

 secure uniform results. . . ." 



The methods presented by the author are 

 those which he, " from long practise on a very 

 large variety of substances, considers to be 

 best adapted for the purposes in hand." 



In its limited range of seventy-five pages 

 the book endeavors to cover the analysis of 

 sugar-cane, cane-sugar and beet-sugar and 

 their derived products, maple-sugar and maple- 

 syrup, honey, commercial glucose, dextrin. 



starch, condensed milk, milk chocolate, etc. 

 A few tables and illustrations are scattered 

 through the text. 



There is undoubtedly room on the shelf of 

 many an analyst for a work which shall give 

 tested and tried methods for the analysis of 

 sugar and allied, saccharine, products. The 

 author has brought together some material of 

 value for this purpose; there is however — 

 in spite of his conviction — room for consid- 

 erable doubt as to whether his choice of 

 methods would always commend itself to the 

 approval of other experienced analysts. 



In discussing the determination of sucrose in 

 raw sugars, the use of Wiley's correction fac- 

 tor is recommended to obtain " the true polar- 

 ization in sugars polarizing over 90°," if the 

 temperature of polarization varies from 20° 

 C, and then the author goes on to state that 

 such correction is not applicable " where the 

 reducing sugars exceed 3 per cent., as differ- 

 ences in temperature affect the reducing 

 sugars more strongly than sucrose." 



It would be interesting to learn why and 

 how this arbitrary limitation of 3 per cent. 

 has been decided upon by the author, and how 

 he would obviate the disturbing influence of 

 the precipitate-error in clarification which 

 tends to offset the reduction in the specific 

 rotatory power of sucrose caused by an eleva- 

 tion of temperature above the temperature at 

 which the polariscope has been graduated. 



The concise, not to say terse, manner of 

 expression employed in the book is a good 

 feature, yet a few additional words of ex- 

 planation would not have been out of place in 

 several instances, for example in giving the 

 formula to be used in the Clerget method 

 (p. 11). The novel way of printing the names 

 of several of the more common sugars (p. 36) 

 is apt to introduce more confusion in this 

 already troublesome issue and the data given 

 in that table are not always correct — thus, 

 f. i. raffinose is hydrolyzed by invertase into 

 d-fructose and melibiose, and not into d-glu- 

 eose and d-galactose, as stated. Hydroliza- 

 tion of raffinose into d-galactose and sucrose 

 is effected by emulsin. 



F. G. WiECHMANN 



