CH EMISTRY. (MISCELLANEOUS.,) 



141 



enlarged our conceptions of the chemical power 

 of tlie vegetable cell. 



Tin- chemistry of the two nitrifying organisms 

 funii.-hes .-in excellent example of the way in 

 \\liii-li en-lam special functions, indicating nar- 

 rowly limited lines of work, are exercised by in- 

 dividual species of bacteria. By one of these or- 

 piniMiis ammonium carbonate is oxidized and 

 the nitrogen converted into a nitrite. By the 

 >ecniul organism nitrites are converted into ni- 

 trates. The nitrous organism can oxidize am- 

 monia to nitrite, but it can not change a nitrite 

 into a nitrate. The nitric organism, on the other 

 hand, oxidizes nitrites readily, but it can not 

 oxidi/e ammonia. Both organisms are in all fer- 

 tile soil, but the formation of nitrites is not usu- 

 ally perceived, as they are at once converted into 

 nitrates. The organisms develop and perform 

 their functions only when certain inorganic salts 

 supplying phosphates, sulphates, potassium, cal- 

 cium, and magnesium are present. The contin- 

 ued omission of one of these has been proved in 

 several cases to bring about a cessation of growth 

 and function. Nitrogenous food is amply fur- 

 nished to these organisms by ammonia, the nitrite 

 or nitrate of which is intentionally added to the 

 solution. It is unnecessary to supply them with 

 any carbonaceous food except carbonates, bicar- 

 bonates being preferred. The fact of the conver- 

 sion of carbonates into organic cell substance has 

 been proved in the case of the nitrous organism ; 

 it is at present assumed to be also true of the 

 nitric organism. A third organism has been ob- 

 tained from soil by Winogradsky, which possesses 

 the remarkable power of assimilating the free 

 nitrogen of the atmosphere. To accomplish this 

 assimilation it is simply necessary to grow it in 

 a solution containing sugar (dextrose) and the 

 necessary salts, no combined nitrogen being sup- 

 plied. Under these circumstances a vigorous 

 growth of the bacillus takes place, the sugar un- 

 dergoes a butyric fermentation, and at the end 

 of the operation it is found that the culture has 

 acquired nitrogen. We have no clew as yet to 

 the mode in which the nitrogen enters into com- 

 bination ; but it is evident that in this case, as 

 in the nutrition of the nitrous organism, the diffi- 

 cult piece of chemical work forms but a small 

 part of a much larger reaction that is at the same 

 time in progress, and with which it is essentially 

 connected. 



A paper by H. T. Brown and G. H. Mom's 

 deals with the occurrence, relations, and physio- 

 logical significance of the starch, diastase.* and 

 sugars contained in foliage leaves. The work 

 originated in an attempt to discover the explana- 

 tion of the conditioning effect of " dry hopping," 

 or the addition of a small amount of dry hops to 

 finished beer. This was ultimately traced to the 

 presence in the hop strobiles of a small but ap- 

 preciable Quantity of diastase, sufficient to cause 

 slow hydrolysis of the noncrystallizable products 

 of starch transformation left in the beer, and to 

 reduce them to a condition in which they can be 

 fermented by the yeast. The authors were then 

 led to inquire into the first formation of the 

 starch in the chloroplasts of the foliage leaf, the 

 mode of its dissolution and translocation in the 

 plant, and the nature of the metabolized prod- 

 ucts; the results obtained are antagonistic to 

 the assumption made by Sachs, that all the 



I m /ducts of assimilation at some time take the 

 form of starch. Only a small portion of the 

 assimilated material exists at any one time as 

 starch. The fluctuations in the amount of starch 

 in leaves were also determined. Wortmann's re- 

 cent denial that diastase plays any part in the 

 dissolution and translocation of starch in leaves 

 is pronounced incorrect. The authors show that 

 instead of leaves containing little or no diastase, 

 every leaf examined by them contained sufficient 

 diastase to transform far more starch than the 

 leaf can have contained at any one time. The 

 products of the hydrolysis of starch by leaf dia- 

 stase are identical with those formed by malt 

 diastase, maltose having been directly separated 

 from the leaves ; leaf diastase does not convert 

 maltose into dextrose, but the leaf contains an 

 enzyme capable of inverting cane sugar. The 

 amount of diastase present varies greatly in dif- 

 ferent plants, and within narrow limits even 

 varies in the same plant at different times. It is 

 very high in the case of the leguininosae. Any 

 conditions that favor a decrease in the leaf starch 

 result in an increase of the leaf diastase ; thus a 

 marked increase in diastatic activity is observed 

 in leaves kept in darkness. Contrary to Wort- 

 mann's statement, leaf diastase can attack the 

 starch granule under certain conditions ; no evi- 

 dence could, however, be obtained of the disap- 

 pearance of starch in killed leaves under the in- 

 fluence of the contained diastase, and the authors 

 are led to conclude that the first stage of dissolu- 

 tion of the starch granule in the leaf is in some 

 way or other bound up with the life of the cell. 

 From experiments on the leaves of tropaeleum, 

 the authors draw the following conclusions: 

 Cane sugar is the first sugar to be synthesized 

 by the assimilatory processes. This sugar ac- 

 cumulates in the cell sap of the leaf parenchyma 

 while assimilation is progressing vigorously, and 

 when the concentration exceeds a certain point 

 starch begins to be elaborated by the chloroplasts 

 at the expense of the cane sugar. This starch 

 forms a more stable reserve material than the 

 cane sugar, and is drawn on only when the latter 

 more readily metabolized substance has been 

 partially used up. Cane sugar is translocated as 

 dextrose and levulose and the starch as maltose. 

 From the invert sugar derived from the cane 

 sugar the dextrose is more readily used up for 

 the respiratory processes, and possibly also for 

 the new tissue building than is the levulose ; 

 hence in a given time more levulose than dex- 

 trose must pass out of the leaf into the stem. 



Miscellaneous. Increased attention is given 

 to the study and utilization of the disinfecting 

 properties of peroxide of hydrogen. Richardson 

 has shown that the antiseptic action of the sun 

 on urine is due to the production of this sub- 

 stance; for samples. exposed to the sun remained 

 clear, and on examination were found to contain 

 it, while similar samples kept in the dark became 

 turbid and contained none. Traugott has point- 

 ed out as a result of his investigations that it may 

 be substituted for corrosive sublimate and car- 

 bolic acid in all cases where the period of contact 

 is not less than from a quarter to a half an hour: 

 but that it is not suitable when rapid disinfection 

 is required. Being innocuous and not injurious 

 to clothing, etc., it is a safer disinfectant for gen- 

 eral application than the others, but its cost is 



