AGRICULTURAL BOTANY. 751 



Erepein is found more widely distributed in plants than the fibrin-digesting pro- 

 teases. In another publication i K. 8. R., 17, p. 542) the author concluded from his 

 Btudies of papain thai it contained both erepsin and a fibrin-digesting enzym similar 

 to pepsin, [n the present paper the author reports having found by the same methods 

 of study these two proteases in the juice of the pineapple, in yeast, mushrooms, malt, 

 hyacinth bulbs, and in the liquor found in the pitchers of Nepenthes. 



[n summarizing the results of the investigations the author saw- thai peptolysis 

 appears to take place within a range extending from distind alkalinity to a degree of 

 acidity quite beyond thai occurring in nature. On the other hand, fibrin-digestion 

 is much less uniform, showing wide and striking differences, yeast, mushroom, malt, 

 and Nepenthes being limited to acid reactions, while fibrin-digestion took place in 

 alkaline reactions with papain, pineapple, and hyacinth bulbs. 



All the plant- examined contained ereptase. In some of these it was found to be 

 associate.! with a greater or less proportion of a peptase, bul in no plant was a pep- 

 tase found to exisl unassociated with ereptase. 



The nitrogen nutrition of chlorophyll-bearing- plants, ( ). Treboux (Ber. 

 D, nt. Bot. Gesell., 22 {1904), ZVb. 10, pp. 670-572; abs. in Jour. Cliem. Soc. [London], 

 88(1905), No. 510, II, p. 276). — A preliminary report is made of investigations on 

 the availability of various forms of nitrogen for plants. The studies included nearly 

 all groups of chlorophyll-bearing plants and comparisons were made with some fungi. 



The summary account given shows that nitrogen as nitrites is generally available 

 when in alkaline solutions, but poisonous in acid solutions. The poisonous action 

 depends upon the degree of concentration of the solutions, and for the uitrites it is 

 a little lower than for the ammonium salts. In comparing nitrates and uitrites it 

 was found that they possessed practically the same efficiency, although in a few 

 instances nitrates proved of greater nutritive value than nitrites. Ammonium salts 

 were found to he still more available than either nitrates or nitrites. 



In comparing the organic compounds, annus and amids were studied, and for tin- 

 lower groups of plants they were found to be aboutequally valuable. For the higher 

 chlorophyll-bearing plants the amids are said to be less assimilable. The ammonium 

 salts of corresponding organic acids are more assimilable than the amin acids. The 

 author believes that asparagin and similar compounds are split up by enzyms and 

 the ammonia liberated, and further that they are not directly used by the plant in 

 forming proteids. It is claimed that ammonium salts are most suited to the nitro- 

 gen nutrition of chlorophyll-bearing plants, and that the intervention of nitrite and 

 nitrate bacteria is not always necessary. 



Studies of endotrophic mycorrhiza, I. Galland (Rev. Gen. Bot.,17 ( 1905), No8. 

 193, pp. 5-48; 194, pp. 66-85; 195, pp. 128-186; 197, pp. 228-289; 199, pp. 818-825; 

 202, pp. 423-433; 203, pp. 479-500, pis. 4, figs. 6). — The author has made anatomical 

 and biological studies of many forms of endophytic growth, some of which are bul 

 little known. His investigations have shown the possibility of grouping the mycor- 

 rhiza into -4 series. 



In the first serie.-, which is represented by A rum maculatum, the mycelium alter 

 penetrating the cortex of the root develops among the cells, terminating in haustoria, 

 which limit further growth. In the second series the mycelium penetrates the cells 

 and the haustoria are developed latterly, their growth being indefinite. This type 

 is represented by Paris quadrifolia. In the third series, typified by the Hepaticae, 

 the mycelium spreads over the soil and lower surface of thethallus. It enters the 

 host through the rhizoids and develops within the plant cells, where the haustoria 

 are transferred into spongioles. The growth of the mycelium is indeterminate. The 

 fourth series is found among the orchids, where the mycelium is always intracellular 

 and indefinite in growth and assumes a closely knotted development. 



Aside from these distinguishing characters, all kinds of mycorrhiza show a uni- 

 formity of constitution and cytological structure of the mycelium, and the presence 



