BOTANY. 423 



seeds and plants were collected by the special explorers of the Section, iirincipally 

 by D. G. Fairchild and W. T. Swingle. 



Plant physiology, W. F. Ganong {New York: Henry Holt & Co., IDOl, jij). VI -f- 

 147, fig^. So). — This book is designed principally for practical use, and with few excep- 

 tions all the experiments and reconnnendations described have been repeatedly tested 

 by the. author and his students. Detailed directions are given for the construction 

 of a greenhouse and physiological laboratory, both of which are essential to the prose- 

 cutiDn of a course of study such as is outlined. The apparatus, appliances, and jilants 

 for study are described and the more common methods of manipulation are clearly 

 stated. The outline of a course in experimental jilant physiology is given which 

 includes a study of the structure and properties of protoplasm, the nutrition of plants, 

 growth, reproduction, irritability, locomotion, and protection. In connection with 

 the different chapters, bibliographies are given of important works which should be 

 consulted by the student in the prosecution of the course. 



Influence of various organic substances on the respiration of plants, W. 

 Palladin (Rev. Gen. Bat., IS {1901), Nos. 145, pp. 18-32; 146, pp. 93-96; 147, pp. 

 127-136). — In a previous publication (E. S. K., 6, p. 194) the author has shown that 

 etiolated leaves of beans, which are rich in proteids, respire very feebly while those 

 lacking such material, if grown in a saccharose solution, have their respiration con- 

 siderably increased. In the present paper the author gives an account of experi- 

 ments in which a number of different carbohydrates have been tested to ascertain 

 their influence upon the respiration of plants. Experiments were made by cutting 

 off the growing tips of etiolated plants and dividing them into 2 lots. One lot was 

 placed in shallow vessels containing a solution of saccharose, and the quantity of 

 carbon dioxid given off by this plant in a certain time was taken as the unit of com- 

 parison. The other lot of leaves was placed under identical conditions, except that 

 a different carbohydrate was used, and the quantity of carbon dioxid liberated by 

 this second plant was compared with that of the first. The carbon dioxid was 

 determined by the use of Pettenkofer tubes, and in a similar manner the nondigesti- 

 ble proteids were determined by the Stiitzer method, and the total nitrogen by the 

 Kjeldahl method. As a result of the experiments the author found that the energy 

 of respiration depends upon the substances given the plants. Of those investigated 

 the greatest amount of carbon dioxid i)er 100 gms. of fresh plant substance was 

 secured with fructose followed by glucose, saccharose, maltose, raffinose, glycerin, 

 and mannite. The proportion of carbon dioxid liberated per 100 gms. of fresh weight 

 of the plants, during 1 hour, is shown in tabular form. The author also determined 

 that in the absence of carbohydrates the nondigestible proteids not only were not 

 diminished during the growing of the i^lants, but were increased to an appreciable 

 degree. However, the increase was nmch greater when solutions containing some 

 form of sugar were at the disposal of the plant. In one case where the etiolated 

 bean plants were placed in water culture, the nondigestible proteids in 4 days increased 

 13 per cent, while in the second culture containing saccharose, in the same time, the 

 quantity of proteids was increased 39.5 per cent. 



Studies concerning variegation, H. Timpe {Inaug. Diss., GoUingen, 1900, pp. 

 124; ahs. in Bol. Centbl, 85 {1901), No. 3, pp. 75-77).— K report is given of some of 

 the phenomena attending variegation as ascertained in the study of a large number 

 of plants. As a rule, the variegated portions of leaves are thinner than the green 

 parts, the palisade parenchyma and intercellular spaces being considerably reduced. 

 The quantity of tannin in leaves is usually greater in the inner tissues of the varie- 

 gated areas than in the green parts, although tannin is sometimes entirely wanting 

 in the variegated portion of the leaf. Starch is normally deposited only in the green 

 parts of leaves, while reducing sugars are most abundant in the colorless portions. 

 From the sugar solutions in the variegated portions of the leaves a considerable 

 quantity of starch is formed, which is colored a reddish violet with iodin. Variegated 

 monocotyledonous plants do not transform the sugar in their cells into starch. 



