'38 



NATURE 



[November 30, 191 1 



cernin^' economically important plants. This advan- 

 tage has been utilised by Prof. Kraemer to the fullest 

 extent; indeed, it mifjht be considered by some to 

 have been carried rather too far, for the section on 

 fhe " Classification of Angiosperms " deals with medi- 

 cinal plants only. The botamcal portion of the work 

 is well written and abundantly illustrated; it is char- 

 acterised by the comparatively small amount of 

 attention piven to the lower forms of vegetable life, 

 the alga? and fungi occupying only thirty-six pages, 

 whereas in text-books of botany these two groups are 

 usually treated in detail that is often considered un- 

 necessary for the pharmacognosist. 



Part ii., "Pharmacognosy," is subdivided into four 

 chapters, dealing respectively with crude drugs, pow- 

 dered drugs, reagents, and micro-analysis. As the 

 first chapter comprises only 178 pages, and deals with 

 a large number of crude drugs, it is evident that the 

 space allotted to each can be but small. The descrip- 

 tions of the drugs are accordingly very concise, and 

 the methods by which those that are unorganised are 

 produced have been perhaps unduly reduced, but the 

 constituents have received careful and sufficient treat- 

 ment. Thus the accounts of the production of such 

 important drugs as aloes, catechu, guaiacum, rubber, 

 &c., can convey to the mind of the student but an 

 imperfect idea of the various steps in the processes 

 and their effect upon the drug obtained. To these 

 details a little more space might well be given without 

 imduly increasing the size of the work. Credit, how- 

 ever, must be given to the author for including a 

 large number of drugs of comparatively rare occur- 

 rence, and thus making this section of the work more 

 complete than is usually the case with text-books 

 designed for the use of the student. Chapter 

 ii., dealing with powdered drugs, has also been 

 much elaborated. In addition to those with organised 

 structure, it includes a number of structure- 

 less drugs (aloes, myrrh, &c,), as well as a few- 

 definite chemical compounds. The key to their identi- 

 fication, based primarily upon the colour, is one of the 

 most complete that has been published. The chapter 

 is abundantly illustrated, and contains descriptions of 

 the microscopical characters of so many drugs that 

 it cannot fail to be of service to the experienced micro- 

 scopist as. well as to the student. 



Chapter iv., " Micro-analysis," deals with the identi- 

 fication of the crystals found in drugs and their pre- 

 parations by crystallographic methods, and the time 

 has arrived when these methods must be adopted in 

 the study of such crystals if any real progress in that 

 direction is to be made. It is undeniable that at 

 present the crystals observed in drugs are often very 

 loosely described, and that their identification fre- 

 quently rests on very insufficient grounds. This 

 part also includes the description and illustra- 

 tion of the crystalline forms of a number of active 

 constituents of drugs, such as brucine sulphate, 

 codeine sulphate, cubebin, &c., and is to be regarded 

 as suggestive (which is certainly the case) rather than 

 as complete. 



It w-ill thus be seen that Kraemer 's text-book is a 

 valuable contribution to the literature of pharma- 

 cognosy. It shows how medicinal plants mav be 

 NO. 2196, VOL. 88] 



utilised in the study of botany; it deals with a l;. 

 number of drugs; it gives instruction in their iden 

 cation in the powdered state, and it suggests 11 

 upon which microscopical investigation may be pr 

 cuted. The author is to be congratulated on 

 success of his labours. Hbnry G. Grebnisi 



THE CHEMISTRY OF BLEACHING. 

 The Principles of Bleaching and Finishing of Cot 

 By S. R. Trotman and E. L. Thorp. Pp. xii + ; 

 (London: C. Griffin and Co., Ltd., 1911.) Pi 

 16s. net. 



THE book before us is an attempt to blend 

 account of the most recent advances in the p 

 cesses of bleachinj;^ and finishing of cotton goods with 

 an equally up-to-date account of the scientific p*^"- 

 ciples which form the basis of these processes. > 

 an attempt is comparatively rare in connection wiw 

 manufacturing processes, and on that account ak 

 the book ought to be welcomed. But when, as 

 find, the attempt has been highly successful, 

 authors must be congratulated on having produc 

 a work of great value to all concerned in this 

 portant industry. 



The book opens with an account of the structui 

 and composition of cotton fibre, the means of testing 

 its strength, twist, &c., followed by an account of the 

 carbohydrates, such as starch and the sugars which 

 are of importance to the bleacher, A full account is 

 given of the different kinds of water, and of the 

 means of treating it so as to make it suitable for 

 bleaching purposes. The importance of the qualitv of 

 water supplied to the works is too often overU 

 by the bleacher, who ought to know that good re;^-. 

 in bleaching largely depend on the quality of wi" 

 used, and that the pure white required for some gc 

 cannot be obtained if certain waters are used. 



One of the most interesting chapters in the '■ 

 is that in which the influence of bacteria in bleai 

 is discussed. The authors show that cotton ma 

 infected with bacteria at almost every stage o 

 manufacture, and the principal causes are the fc 

 ing :— 



(i) Impure water for steeping. 



(2) Incomplete removal of protoplasmic consiiti 

 during bleaching. 



(3) Allowing goods to lie about in a damp condition, 

 especially in warm weather. 



(4) Insufficient cleanliness of plant or buildings. 



(5) The use of inferior materials, e.g. low-grade 

 starches and glues. 



(6) The careless storing of finished goods. 

 The results of bacterial damage are frequ 



coloured spots, each spot being a colony of uic 

 organism. Sometimes the whole piece of cloth be- 

 comes infected, and has the appearance of having 

 been dyed. A piece of lace examined by the authors 

 left the finisher apparently perfect, but subsequentlj 

 developed a pink colour. 



"A microscopic examination showed the presence oi 

 numerous very fine hyphae interlaced with the cotton 

 fibres, and subsequent plate cultures upon a starch 

 medium similar to the dress used for the lace prove<] 

 the presence of a chromogfenic mould, which was 



