Mat 7, 1915] 



SCIENCE 



687 



starehes. Dr. Eeicliert lias replaced exact 

 quantitative methods by those which under 

 certain conditions might have a confirmatory 

 value, but certainly are of no specific impor- 

 tance, as will be shown later, so that independ- 

 ent investigators may be able to confirm his 

 observations and distinguish one species or 

 genera from another. It is only necessary to 

 read carefully a work like that of Solereder 

 on the " Systematic Anatomy of the Dicoty- 

 ledons " to appreciate the nature of the task 

 that confronts an investigator who attempts 

 to solve a fundamental problem such as Dr. 

 Eeichert has attempted. 



Before critically examining the work it 

 may be desirable to mention the contents of 

 these two large volumes. Nearly 300 pages 

 are devoted to a resume of the important 

 monographs and some of the important papers 

 on the starches. The best part of this portion 

 of the work is the translation from Naegeli's 

 monograph on " Die Starkekorner," giving his 

 classification of some 1,200 starches. This 

 comprises nearly 100 pages. Any review of 

 the literature on starch must be unsatisfactory, 

 as it is likely to be inadequate, and this is 

 especially true of the summary by Dr. Eeichert. 

 It would have been far better in a memoir like 

 this had Dr. Eeichert placed in chronological 

 order the literature which he cited so that it 

 might be consulted or referred to by the stu- 

 dent and the investigator, particularly if he 

 intended this to be a work of reference on 

 starches. 



In Chapter VI. we find a discussion of some 

 of the methods that the author considers might 

 be employed in an investigation of this char- 

 acter and which involved the study of over 

 300 starches, which he isolated from as many 

 different plants. He employed essentially six 

 different methods: (1) Histological method, 

 involving the study of the form, markings and 

 size of grains. (2) Polariscopic properties, 

 i. e., reactions using polarized light both with 

 and without selenite. (3) Iodine reaction, 

 using 0.125 per cent, and 0.25 per cent, of 

 Lugol's solution. (4) Action with aniline 

 dyes, using gentian violet and safranin, using 

 5 c.c. of a solution containing 0.05 per cent, of 



aniline dye. (5) Temperature of gelatiniza- 

 tion, which was determined with a specially 

 constructed water bath, and in which was 

 placed test tubes containing a small quantity 

 of starch with 10 c.c. of water. (6) Several 

 swelling reagents were used, viz., chloral- 

 hydrate-iodine solution, chromic acid in the 

 form of a 25-per-cent. solution; ferric-chloride 

 solution consisting of equal parts of a satu- 

 rated solution in water, and Purdy's solution, 

 which was made up of equal parts of the 

 standard solution and water. 



In the preparation of the starches, the mate- 

 rial was comminuted, mixed with water, 

 strained through cheese cloth, centrifugalized 

 and washed with water and re-centrifugalized 

 to remove as much impurity as possible. 



The various starches were photographed 

 both with and without polarized light. Some 

 of these photographs are very excellent and 

 in some instances may be of some scientific 

 value. For the most part, however, unless 

 photographs of starches are supplemented with 

 drawings they lose much of their interest and 

 significance. 



Great stress is laid by the author on the 

 different reaction intensities of the several re- 

 agents on any given starch and these have been 

 set forth graphically in the form of curves 

 with a view of affording a clear presentation 

 of the quantitative reaction peculiarities of the 

 starches and permit of comparison between 

 them. " In the construction of the charts the 

 abscissas have been used to express the degree 

 of polarization (P), the intensity of the 

 iodine reaction (I), the intensity of the 

 gentian violet reaction (GV), the intensity of 

 the safranin reaction (8), the temperature of 

 gelatinization (T), the time-reaction of 

 chloral hydrate-iodine (CHI), the time-re- 

 action of chromic acid (OA), the time-reaction 

 of pyrogallic acid (PA), the time-reaction of 

 ferric chloride (FG), and the time-reaction of 

 Purdy's solution (PS). The letter or letters 

 as above given in parentheses each lie at the 

 head of a special column or ordinate, and 

 indicate the agent, while those of the abscissas 

 give the values of the reactions. The letters of 

 the column under P indicate, respectively, very 



