May 30, 1913] 



SCIENCE 



837 



modern sense of minus are German. In the 

 Bamberger Rechenhuch (1483) the tare to 

 be deducted from the weight of a package is 

 called das Minus. An Italian writer of the 

 fourteenth century used meno to indicate the 

 subtraction of a number to which it was pre- 

 fixed. The symbol itself, — , De Morgan, 

 most sound and erudite of mathematicians, 

 says arose as a merchant's mark. Its adop- 

 tion was helped by its likeness to the obelus 

 used by ancient critics to indicate that a pas- 

 sage should be removed from the text. This 

 obelus or obelisk was a straight horizontal 

 stroke, either simple ( — ), or with a dot above 

 and one below (^-), and in Denmark the 

 sign -f- is used for minus. 



English examples of plus do not occur so 

 early as those of minus; e. g., 1481-90 

 Howard Eouseh. Bhs. (Eoxb.) 417, v. yerdys, 

 mynus the nayle, welwet blake. Cajori says 

 Enestrom shows " that with Widman -j- meant 

 simply 'und' (and)," but how can this be 

 brought to tally with the fact that Widman 

 explicitly directs that the signs — and + be 

 read minus and mer (mehr) ? He uses them 

 as signs already well known in his " Behende 

 und hiibsche Eechnung auf alien KaufFmann- 

 schafft " (1489); "was — ist, das ist minus, 

 und das + ist das mer." 



The adoption of the form -{- would be 

 greatly helped by its likeness to a form of 

 & ^ et, and "Widman seems to have used the 

 long preexistent form + in the two senses, 

 mehr and et. 



George Bruce Halsted 



SCIENTIFIC BOOKS 



Schutzfermente des tierischen Organismus. 

 Ein Beitrag zur Kenntnis der Ahwehrmass- 

 regeln des tierischen Organismus gegen 

 Korper-, blut- und zellfremde Stoffe. By 

 Emil Abderhalden. Berlin, Julius 

 Springer. Eight text figures ; pp. xi -f- 110. 

 Paper cover, 3.20 M. ; bound, 3.80 M. 

 In this little pamphlet Abderhalden gives an 

 interesting survey of a method which the liv- 

 ing organism employs to protect itself from 

 the effects of foreign soluble substances which 

 have entered its circulating juices. Under 



normal conditions, for example, proteids do 

 not reach the tissue cells in their native state, 

 but only as fragments. This degradation of 

 proteids is normally accomplished by the fer- 

 ments of the gastro-intestinal canal, and some 

 of the degradation products, after absorption, 

 are then synthesized by the tissues into its 

 OTSTi characteristic proteid. Native foreign 

 proteids in the circulation are useless and 

 often directly harmful to the tissue cells. 

 However, when this contingency occurs ex- 

 perimentally or through disease, the invaded 

 body is not entirely helpless, but digestive fer- 

 ments are formed in the circulation, possibly 

 from the leucocytes, which attack the foreign 

 proteid and digest it. These protective fer- 

 ments are formed very swiftly and have been 

 demonstrated by Abderhalden in the plasma 

 or serum twenty-four hours after the subcu- 

 taneous injection of the foreign proteid, while 

 the plasma or serum of normal, non-injected 

 individuals shows no trace of this ferment. 



Similar results were obtained by Abder- 

 halden when carbohydrates were injected, or 

 when fats were driven unchanged into the 

 blood by forced feeding. Here again he was 

 able to show the presence of ferments in the 

 blood which were able to split the foreign 

 substance. 



These facts were established by Abder- 

 halden and his pupils largely through the use 

 of the polariscope. When optically active or 

 racemic substances are split by ferment ac- 

 tion, the optical activity of the mixture 

 changes and this change shows, in the first 

 place, that a decomposition has occurred; in 

 the second place, the character of the change 

 may show what substances have been formed, 

 provided that the chemical structure of the 

 original substance used is accurately known, 

 which is the case with many of the optically 

 active polypeptids. 



The facts briefly mentioned above have re- 

 ceived an important application in the diag- 

 nosis of pregnancy. The circulation of the 

 pregnant organism contains cells from the 

 chorionic villi, and the maternal body reacts 

 to these cells by forming peptolytic enzymes 



