526 SUMMARY OF CURRENT RESEARCHES RELATING TO 



polymeric substance, two of its isomers being oxymethylen, C 3 H 6 3 , 

 and glucose, C 6 H 12 6 . The result of complete deoxidation is the 

 production of methylene, CH 2 , a substance which cannot itself exist 

 independently, but which again has a very large number of isomeric 

 hydrocarbons, as diamylene, C 10 H 20 , triamylene, C 15 H 30 , and tetra- 

 mylene, C 20 H 40 ; the highest members of this series being solid and 

 crystallizable. 



With this process of reduction is associated a process of oxidation 

 in the chlorophyll-grains, and the resulting products are derived from 

 the balance of these two processes. The most common stage of 

 reduction reached is that of formic aldehyde. 



Keinke believes that this hypothesis is in harmony with that of 

 Pringsheim regarding the formation of hypochlorin. A portion of 

 the formic aldehyde is reduced to the hydrocarbon condition ; and 

 the hypochlorin results from a condensation of such groups. Passing 

 from the reducing region of the chlorophyll-grain to the respiring 

 portion of the cell, it is there oxidized into the volatile fatty acids. 

 Both formic aldehyde and hypochlorin are very readily oxidizable, 

 and require the protection of the chlorophyll to prevent their 

 oxidation. 



First Products of Assimilation.* — A. Mori has performed a 

 fresh series of experiments, chiefly on Spirogyra, which confirm his 

 previous conclusion that the first product of assimilation in chloro- 

 phyllaceous plants is an aldehyde, probably formic aldehyde, formed 

 according to the following equation out of the elements of carbonic 

 anhydride and water : — CH 2 3 = CH 2 + 2 . 



Absorption of Metallic Oxides by Plants.f — Mr. F. C. Phillips 

 says that the question how far the vital processes of plants are influ- 

 enced by the various mineral compounds presented by the soil to 

 their roots has long been under discussion, but further than to esta- 

 blish the fact that the presence of certain compounds in the soil 

 tends to increase the nutritious elements and promote the growth of 

 particular plants, little has been done towards a complete solution of 

 the problem. 



It is well known that potash tends to increase the quantity of 

 starch, that silica strengthens the stems of the grasses, that oxide of 

 iron is essential to the production of leaf- green, and that phosphates 

 increase the fertility of the soil for cereals, but even as regards these 

 constant elements of every soil, very little can be positively asserted 

 of the precise influence of any one, in the economy of the plant. 



Concerning the part played by the rarer elements, cassium, rubi- 

 dium, copper, nickel, manganese, zinc, and barium, in the assimilation 

 of carbon, nitrogen, and the functions of nutrition, and whether they 

 are beneficial or injurious, nothing whatever is known, although 

 modern refinements in chemical methods have led to their frequent 

 detection both in soil and in plants. That so important a problem 



* Nuov. Giorn. Bot. Ital., xiv. (1882) pp. 147-55. Cf. this Journal, ante, 

 p. 361. 



f Journ. Franklin Institute, cxiv. (1882) pp. 41-9. 



