August 30, 1912] 



SCIENCE 



281 



Fergusson's Percentage Unit of Angular Meas- 

 urement, with Logarithms; also a Descrip- 

 tion of his Percentage Theodolite and Per- 

 centage Compass. By John Coleman Fer- 

 GUSSON. London, Longmans, Green & Co. 

 1912. 8vo. Pp. h:vii4-467. 

 This is one of those costly volumes printed 

 occasionally to advocate some novel idea; not 

 actually incorrect, but yet quite without real 

 value. Such books are full of pathos. One 

 can see in their pages lost yet endless indus- 

 try; painful longing for sympathetic apprecia- 

 tion; indomitable energy; the sacrifice almost 

 of a life-time; and finally the refusal to ac- 

 cept even the kindliest adverse criticism. 

 Were not the theories of Galileo received veith 

 incredulity? Are not my theories met by 

 similar unbelief? Galileo was right. So then 

 must I be also. Such is the fallacious reason- 

 ing consciously or unconsciously in the minds 

 of men like Fergusson. 



The division of the circle has always been 

 made hitherto in equal parts, ordinary de- 

 grees of arc or centesimal degrees. Fergusson 

 proposes to divide the circle into unequal parts, 

 one hundred spaces to each octant, or are of 

 45° as ordinarily measured. To the new di- 

 visions will be attached numbers thus: 1%, 

 2%, . . . 10%, etc., in such a way that the 

 number 10%, for instance, will belong to the 

 angle whose tangent is 0.10, etc. 



The author gives elaborate logarithmic 

 tables computed for this new division of the 

 circle; but it appears from his examples of 

 their use that no saving of time or other ad- 

 vantage has been obtained. He has also had 

 made an engineer's angle instrument provided 

 with the new circle divisions; and has of 

 course been unable to use a vernier. In its 

 place is substituted a most complicated "mi- 

 crometer drum screw." 



The book is not free from humor: we recom- 

 mend the following passage to the engineering 

 and financial experts of Wall Street. 



" A gives X £500 sterling for a half share in 

 the sixth interest that X holds in a mining 

 claim located at Eureka, Nevada, U. S. A. It 

 is plain to everybody that X has received 

 £500 sterling for the half share of his mining 



interest. A, on the other hand, has got for 

 his money an acknowledgment, which, in 

 itself, is a concrete function implying value; 

 and this implied value is dependent on the 

 geological formation of a piece of ground 

 staked out in Nevada, the true value of which 

 A may determine by the aid of a Philadelphia 

 lawyer and a western mining expert. A has 

 received implicit value; X got explicit value." 

 The author asserts that this " simple ex- 

 ample " makes clear " the whole difference be- 

 tween the arithmetical and algebraic systems." 



H. J. 



SPECIAL ABTICLES 



THE PRESENT STATUS OF THE BACTERIOLOGY OF 

 HUMAN LEPROSY 



Since the discovery by Hansen in 1872 of 

 an acid-fast bacillus in the leprous lesion to 

 which he ascribed an etiological role, numer- 

 ous investigators have reported success with 

 its artificial cultivation. It may be stated, 

 however, that prior to 1901 the cultures iso- 

 lated and described by various investigators 

 differed tinctorially and morphologically from 

 the Hansen bacillus of the tissues, and al- 

 though many of these cultures were said tO' 

 have induced experimental lesions similar to 

 human leprosy and to have fulfilled other 

 postulates, no one of them has been univer- 

 sally accepted as the specific organism of 

 leprosy. 



Kedrowski in 1901 described an organism' 

 which he cultivated from the leprous lesion 

 and believed to be the specific bacillus of lep- 

 rosy. This author reported his culture as a 

 non-acid fast diphtheroid bacillus, which when 

 injected into laboratory animals became acid- 

 fast after a sojourn of weeks in the tissues. 

 He advanced the theory that the acid-fast rods 

 seen in human leprous lesions represent but a 

 stage in the developmental cycle of a single 

 pleomorphic species. 



Deycke and Eost and Williams have since 

 reported (1905) upon the successful cultiva- 

 tion from the leprous nodule of an organism 

 similar to that of Kedrowski's together with 

 which they also found streptothrical forms 

 and acid-fast rods. 



