360 



SCIENCE 



[ISr. S. Vol. XXXI. No. 792 



THE BOTANICAL SOCIETY OF WASHINGTON 



The fifty-ninth regular meeting of the society 

 was held at the Ebbitt House, January 29, 1910, 

 at eight o'clock, p.m.; President Wm. A. Taylor 

 presided. The following papers were read: 



Legal Regulation of Plant Diseases: Dr. Haven 

 JSIETCALF, U. S. Bureau of Plant Industry. 



Further Botanical Evidence regarding Coastal 

 Subsidence: H. H. Babtlett, U. S. Bureau of 

 Plant Industry. 

 The full paper will appear in a forthcoming 



number of Rhodora. 



The Use of the Immersion Refractometer in the 



Study of Plant Extracts: H. C. GtOEE, U. S. 



Bureau of Chemistry. 



The Zeiss immersion refractometer, an instru- 

 ment which measures index of refraction of liquids 

 in terms of an arbitrary scale, was shown and its 

 probable usefulness in vegetable physiological 

 studies was illustrated by readings on cane sugar 

 and on eider. The arbitrary scale is so con- 

 structed that in many cases the readings, less the 

 amounts due to the presence of water, are almost 

 exactly proportional to the amounts of dissolved 

 substance. This is particularly true for dilute 

 solutions, e. g., dilute solutions of sugars. Tables 

 can therefore easily be constructed for any sub- 

 stances or groups of substances for which tables 

 are now lacking. Solutions can be examined rap- 

 idly. Small amounts are required, 1 e.c. being 

 sufficient, though more is desirable, and the solu- 

 tion need not be clear. Further, a definite phys- 

 ical constant, the index of refraction, is deter- 

 mined. 



The instrument is brought to the attention of 

 botanists because it is well adapted to field work, 

 and has been found to be very useful in detecting 

 slight differences in sugar content, therefore it 

 may be used in making selections among sugar- 

 containing plants and fruits, and in detecting 

 differences in soluble carbohydrates due to slight 

 changes in environment. The refractometer has 

 been found very useful in the study of the rate 

 of fermentation of apple cider in cold storage. 

 It is also widely used in technical work and in 

 food analysis. 



A preliminary study of the ratio of the scale 

 readings, less 15, the reading due to pure water 

 at 17.5° C, to the per cent, of cane sugar in 

 solution, shows that the ratio varies from 3.75 

 to 4.09 for amounts of sugar from 2.5 to 16 per 

 cent., the figures being as follows: 



Per Cent, of 

 Cane Sugar 

 2.5 

 5.0 

 9.0 

 13.0 

 17.0 



Ratio of Scale Readings 

 less 15, to Per Cent, 

 of Sugar. 

 3.75 

 3.81 

 3.91 

 4.01 

 4.09 



A study of the ratio of the scale readings less 

 15, to the total solids, of 13 samples of freshly 

 pressed cider showed the ratio to be 3.91, with a 

 maximum of 4.09 and a minimum of 3.79. It is 

 practicable, therefore, to work out for a plant 

 juice a factor which will relate the scale readings 

 to the content of total solids. By making a proper 

 allowance, to be determined experimentally, for 

 the readings due to the non-sugar solids, the 

 sugars can probably be estimated with a fair 

 degree of accuracy. W. W. Stockbebgeh, 



Oo7-responding Secretary 



THE ANTHEOPOLOGICAL SOCIETT OF WASHINGTON 



JxT the 441st regular meeting, held February 1, 

 1910, Dr. D. S. Lamb read a paper entitled, 

 " Like Father Like Son : A Study in Heredity." 



After a general introduction the speaker gave 

 especial consideration to variations and illus- 

 trated with many cases taken from Darwin, Keid, 

 Thomson, Woods, Fay and others. As to rever- 

 sions, he was inclined to think that many so- 

 called reversions are simply arrests of develop- 

 ment. He thought that the attitude of writers 

 on heredity now in regard to the inheritance of 

 acquired characters is that of a negative. As to 

 the inheritance of disease, there was no doubt that 

 a tendency to disease was frequently inherited. 

 The probabilities are that the sperm or ovum is 

 affected by the disease of the parent. He dis- 

 believed in telegony and maternal impressions. 

 A brief statement was made of the more impor- 

 tant theories of heredity; he inclined to the 

 Mendelian principle as set forth by Bateson. 



In the discussion Mrs. G. E. Stetson and Dr. G. 

 M. Kober pointed out the importance of the 

 problem of heredity in its relation to practical 

 life, especially to education, marriage, public 

 health, and the treatment of criminals and de- 

 fectives. 



Dr. J. Walter Fewkes exhibited and commented 

 on some drawings of divinities, altars and other 

 paraphernalia of worship made by Hopi Indians 

 under his supervision. 



I. M. Casanowicz, 



Secretary 



