AGRICULTURAL BOTANY. 429 



more important products, thus bringing together plants of widely divergent 

 botanical relationships that are closely allied so far ajs their uses are concerned. 



After giving general directions for the preparation and care of material for 

 study, the author gives chapters on the microscopic studies otf the principal 

 substances found in plant cells, plant structures, etc. The principal proportion 

 of the book is taken up with studies on starches, tropical woods, their character 

 and uses, fibers, and secretory substances such as resins, rubbers, etc. 



Biology of plants, F. W. Negeb {Biologie der Pflanzen auf experimenteller 

 Qrundlage. Stuttgart, 1913, pp. ZZ/X+775, figs. 815).— The author discusses 

 at considerable length the theory of adaptation, and treats of adaptation of 

 plants to light, temperature, water, mechanical stimuli, edaphic adaptations, 

 symbiotism, special adaptations for propagation, etc., the subject being largely 

 presented in such a manner that the book should be of special interest to stu- 

 dents of ecology. 



Researches on irritability of plants, J. C. Bose {London, New York, and 

 Bombay, 1913, pp. XXIV +376, figs. 190).— The author presents the results of 

 his investigations on the irritability of plants, using new electrical devices for 

 recording that are considered superior to the methods formerly applied. 



The two forms of apparatus are called the oscillating recorder and the 

 resonant recorder. In the former the recording surface is so oscillated as to 

 bring it in contact with the recording point. In the second the writing point 

 is made to vibrate at required frequencies, making an intermittent contact 

 with the recording plate. Both when tested gave satisfactory records of 

 response to stimuli of various sorts. 



The author claims from a survey of the response of living tissues that there 

 is hardly any phenomenon of irritability observed in the animal which is not 

 also found in the plant, and that various manifestations of irritability in the 

 plant have been shown to be identical with those in the animal. 



Chemical and physical changes in geotropic stimulation and response, 

 Eva O. Schley {Bot. Gaz., 56 {1913), No. 6, pp. 480-489, figs. 6).— In view of the 

 effect of acidity on the absorption of water and on the growth rate, the author 

 made a study of the concave and convex halves of geotropically stimulated and 

 responding organs for difference in acidity, and incidentally for other features, 

 such as the sugar content. 



It was found that the acidity of the growing shoot is greatest at the tip and 

 decreases downward. The relative acidity of the two flanks of the geotrop- 

 ically stimulated shoots changes during presentation and reaction time. The 

 increase of acidity does not parallel the relative rate of growth on the two 

 flanks. Several plants examined were found to develop in neutral solution a 

 chromogen which acted as a delicate acid-alkali indicator. The percentage of 

 dry weight was found to be greatest on the concave side of the stimulated 

 organs. 



Acidity, gaseous interchange, and respiration of cacti, H. M. Richards 

 (Carnegie l7ist. Washingion Year Book, 11 {1912), pp. 65, 66). — An investiga- 

 tion has been made of the respiration of cacti and the phenomena related 

 thereto under various external conditions. The effects of temperature changes 

 and wound reaction were studied, and parallel with these experiments a series 

 of experiments were conducted to determine the respiratory quotient of cacti. 



In general it was found that the respiration of the young joints is far higher 

 than that of the older but turgid tissue, while that of the latter greatly exceeds 

 the respiration of the mature but inactive plant. The gas interchange was 

 found to be different in the young and old shoots. The younger ones approxi- 

 mated more nearly the usual absorption of oxygen and evolution of carbon 

 dioxid, while the older joints showed a larger use of oxygen, which is said 



