408 



beiug far from drying up after the second year, and thus becoming sub- 

 sequently only a dead tissue. 



I^'FLUE^'CE OF HEAT OF SOIL OX GROWTH OF PLANTS. — The result 



of a recent investigation by Bialoblocki, in regard to the influence of 

 the warmth of soil upon the development of certain cultivated plants, 

 is summed up by him in the following words : The influence of warmth 

 of the soil is made manifest in two directions; in the shortening or 

 lengthening of the period of vegetation, and in affecting the external 

 form of the plant ; the acceleration of growth of vegetation occurring 

 principally in the earlier periods. With an ascending temperature of 

 the soil, vegetation is forwarded up to a certain point. From the mo- 

 ment, however, when this point is reached, an increase of" temperature 

 in the soil actually retards growth. The maximum point of favorable 

 temperature of the soil varies for different i^lants ; but the maintenance 

 of a constant temperature has for its result a more vigorous growth of 

 the plant experimented on. The extreme limit of a constant tempera- 

 ture of the soil at which a growth of the roots can still take place, we 

 .may assume to be below, but very near 104° F. A ground temperature 

 of 50° F. barely allows plants to fulfill completely all their functions of 

 life and conditions of development. An increased ground temperature 

 has no special influence upon the absorption of nutritious matter through 

 the roots ; and the accelerated growth resulting from an increase of heat 

 is usually accompanied by a greater percentage of water in the plant. 



MAKEN'a SUGAR FROM FALLEN CANE. — At a late meeting of the Acad- 

 emy of Medical, Physical, and Natural Sciences of Havana, Mr. de Cas- 

 tro"i)resented a communication of important iiractical moment, bearing 

 upon the feasibility of obtaining sugar from cane that has fallen to the 

 ground and thrown out roots into the earth from its joints. It has gen- 

 erally been supposed that the development of these roots takes place at 

 the expense of the crystallizable sugar; but a critical comparative anal- 

 ysis, made by Dr. Koehl at the plantation Las Cauas, of juice extracted 

 from the normal cane, and from that which had thrown out the roots in 

 question, shows that the development of the latter does not interfere 

 appreciably with the amount of sugar in the cane ; or, at least, to so 

 slight an extent as not to affect the saccharine richness of the plant. 

 For this reason fallen cane, and cane which has been thrown down by 

 hurricanes, can be turned to almost as good account as if it had 

 remained erect. 



Lactarin. — Lactarin is a substance which has been lately introduced 

 as a substitute for albumen, for manufacturing purposes; and it is said 

 to have great advantages on the score of cheapness and convenience of 

 preparation. It is essentially a form of caseine, rendered impure by a 

 little fat and the salts of milk. For use it is diluted with water, dis- 

 solved in ammonia, and then added to the coloring matter. 



Determining tannin in oak bark. — A method lately introduced by 

 Loewenthal for determining the amount of tannin in oak bark is based 

 upon the fact that tannin, in the presence of indigo, is decomposed hj 

 permangarjate of potash in such a manner that, with the final disap- 

 pearance of the blue color, the last trace of the tannin is also decom- 

 posed. For this inquiry the following liquids are needed : First, a solu- 

 tion of indigo carmine ; second, a solution of tannin ; third, a solution 

 of the chameleon mineral or permanganate of potash ; and fourth, a 

 solution of oxalic acid. 



Application of potash to plants. — Professor Xobbe, of Tharand, 



