BOTANY. 825 



tions of podinm nlilorid, potassium nitrate, or glycerin, tliey are no lon*i;or al)le to 

 withstand tlic teiuperature of li(jiii(l air. It is believed possible to determine the 

 value of the osmotic pressure for any given eell l)y which the temperature at which 

 its vitality will be destroyed. 



The periodicity of root growth, J. Hammerle (Beiir. Wiss. BoL, 4,pt. 2, pp. 15; 

 abx. ill B(jt. Cunthl., SS {1901), No. 4, P- 107). — The roots of Acer pscudoplatanuH were 

 foun 1 to make their principal growth in the spring of the year and in the autumn. 

 During the months of January, February, and March there was an almost entire ces- 

 sation of growth. During nud-suuuner a similar cessation of growth was noticed. 

 Investigations were made upon a number of 1 to 5 year old trees grown in the open 

 and in pots, the results obtained confirming previous (jbservatitjus. The duration 

 anil amount of growth was found to be influenced by age, soil, climate, etc. Con- 

 trary to the observations reported by others, the author was unable to find any root 

 growth taking place in the red beech during autumn. Willows, oaks, and hazel 

 make strong root growth in the fall of the year, and the hazel showed considerable 

 growth during January. 



The structure of the sprouts from various trees, M. Duihard (Compt. Rend. 

 Acad. Sci. 7V//'/.s', l.iJ {1901), No. -22, pp. lS5G-l--,oS).—X study is reported of the 

 sprouts which rise from the roots of poplar, elm, hazel, etc., from dormant buds of 

 the oak, and from the cambium layer of oak, black poplar, etc. The.se sprouts show 

 by their anatomy the characteristics of herbaceous plants. Their growth is rapid, 

 and they have elongated internodes and develop stipules wliich persist for a long 

 time. There is little differentiation of tissues, particularly of the protective and 

 strengthening tissues. There is a considerable production of cortex in proportion to 

 wood, and the whole ripens poorly. Within the same genus of plants the structural 

 cliaracteristics of the shoots are most nearly alike for those species whicli are nearly 

 related. 



The form and manner of root growth of some trees, ]\I. Busgen {Allg. Forst u. 

 Jii(/d /lij., f!7 { 1901), Aug., pp. 273-278; Sept., jtp. ;i0.5-.i09,Ji(/.^. 4). — The root systems 

 of a number of trees are described. The time of the most important root growth of 

 a number of trees and shrubs, as shown by the observations of the author and others, 

 is indicated l)y a chart. The principal species reported ujton are ash, birch, beech, 

 alder, oak, maple, poplars, willows, elms, locust, spruce, pine, larch, white fir, etc. 

 Considerable variation is shown in the period of maximum root growth of the differ- 

 ent species, as reported by the different observers. As a rule the most of the root 

 develojtment takes place between Ajjril and October, with little or none in December 

 and January. Exceptions are noted, however, and there seems to have been a ces- 

 sation of growth during the sinnmer months in some species, and willows, maples, 

 lindens, horse chestnut, and a few shrubs are shown to ha\e increased their root 

 development during December and January. 



Concerning the proteid formation by plants, W. Zaleski {Tnaug. Dm., Khar- 

 kov, 1900; ah.s. ill. Bot. CeitthL, S'7 (1901), No. 8, j>p. 277-282).— X review is given of 

 the literature bearing upon tlie subject of proteid synthesis by i)lants, and experi- 

 ments conducted by the author are described, from which he draws some conclu- 

 sions. The subject is considered to be still in an indefinite state as to some of the 

 ])heiiomena. Proteid formation from organic nitrogen in the dark, j)roteid regener- 

 tion from metaboliir ])roducts, and proteid synthesis from nitrates are discussed at 

 some length. Exj)eriments with onions, i)otatoes, and narcissus bull)s showed that 

 there was an increase in the protei<l content when kept in the dark, and the author 

 claims that it was not made at the expense of asparagin, but from other little-known 

 nitrogenous bodies. Experiments with etiolated lupine seedlings showed their 

 ability to build up proteids from some of their metal)olic products, and experiments 

 with sunflower leaves kei>t in the dark showed they were able to form proteids from 

 nitrates and sugar. 



