BOTANY. 741 



presence of this is to be explained the transniission of variegation by means of grafts 

 and cuttings. 



Experiments on cereal improvement at Olbersdorf, G. Swoboda {ZUchr. 

 Landiu. Versuchsiv. Oesierr., 5 {1902), No. 11, pp. 12T2-1288). — A detailed account is 

 given of experiments which have been carried on at the station of Olbersdorf in the 

 improvement of varieties of cereals. Spelts and oats were the subject of the improve- 

 ment experiments, the object being to secure varieties better adapted to cultivation 

 under conditions of elevation, temperature, etc., which prevail at that station. Pota- 

 toes were also experiiiiented with, but are not reported upon in any detail. 



The g-ermination of potato tubers, II. Vochtino {Boi. Zfg., 1. Aht., 60 {1902), 

 No. 5, pp. 87-114, pis. 2; <ibs. in Jour. lioi/. Miero.'i. Soc. ILondon], 1902, No. 4', P- 452). — 

 There was found to be a close correlation l:)etween the temperature and the manner 

 of development of the sluxjts Hi)ringingfroni potato tubers. At a temperature which 

 only slightly exceeded the lower limit at which gernaination begins only tuber-bearing 

 shoots were produced, while at the optimum temperature these shoots were exclu- 

 sively developed. In the former case the root development of the plants was very 

 small, while in the latter roots were abundantly developed. The amount of water 

 in the soil was also found to be closely related to the mode of growth. If little or no 

 water was present there was but slight development of roots, and no leaf shoots were 

 formed, but only tubers. On the other hand, with a plentiful supply of water, numer- 

 ous roots and leaf shoots appeared but no tubers. An increase in the supply of mois- 

 ture in the air w'as found to favor the development of leaves on the shoots where only 

 scales were formed in insufficient moisture. The amount of oxygen in the atmos- 

 phere was found to exert no appreciable influence during the course of germination. 



Aleurone gfrains in oily seeds, B. Gram (A". Danske Vidensk. Selnk. Skr., 6. s^er., 9 

 {1901), pp. 303-336, pis. 4; abs. in Jour. Roy. Micros. Soc. ILondon], 1902, No. 4, pp. 

 442, 443)'. — The author has'examined the character and reaction of the tegument, 

 fundamental mass, globoid, crystal, etc., elements of oil-bearing seeds. The seed 

 coat was found to be highly refractory. The fundamental mass consisted mainly of 

 albuminoids which showed different degrees of solubility in dilute caustic potash for 

 the different kinds of seed. In the globoid not only were the acid phosphates of 

 calcium and magnesium found, but also succinic acid, and from their behavior with 

 various solvents the globoids seemed to have a uniform composition. The investiga- 

 tions relating to the presence of alkaloids were of a negative character. From the 

 crystals present succinic and oxalic acids and magnesium, calcium, and potassium 

 were obtained. The difference in resistance of the crystals to different reagents is 

 due to differences in their chemical composition. In most cases the author concludes 

 that the crystalloids are of a very complex nature. 



Enzyms of the tea leaf, II. H. Mann {Jour. Asiatic Soc. Bengal, 70 {1901), II, 

 No. 2, pp. 154-166). — After briefly reviewing the chemistry and physiology of the 

 tea leaf, the author gives an account of investigations on the enzyms which are found 

 in the tea leaf and to which the character of the prepared tea is said to be due. It is 

 said that an oxydase occurs in the leaf of the tea plant, and that this is the principal 

 agent which causes fermentation and coloring of the leaf. It is most active at tem- 

 peratures below 55° C, and is destroyed at a temperature of 80°. It occurs in 

 greatest abundance in the unopen leaves at the tip of the' shoot. The quantity 

 tlecreases as the leaves grow older, but the leafstalks contain almost the same 

 amount as the tip leaf. In leaves of the same general type those which contain the 

 most of the enzym make the most highly flavored tea, and the increase in the enzym 

 of the leaf seems to be related to the amount of phosphates in the soil. The amount 

 of enzym in the leaf increases rapidly during the process of withering the leaves, a 

 fact that makes it probable that this ferment performs much more important func- 

 tions in the manufacture of tea than has hitherto been believed. Other enzyms 

 were found to occur in the tea leaf, but as yet no evidence has been obtained to 

 show that tney are ot great importance in tea manufacture. 



