57S 



NA TURE 



[October 13, 1892 



•hieing them to carbonic acid and water, in order to obtain the 

 necessary heat and energy ; or they can oxidize by Riving off" 

 oxygen. The first may be termed intracellular, and the second 

 extra-cellular acting organisms. Amongst the intra-cellular we 

 have primarily, the u-ual ferments of decay, which assimilate 

 and respire at the expense of the carbon compounds. In some 

 cases the organisms have accommodated themselves to seemingly 

 most remarkable materials for respiration, the combustion of 

 which affords the necessary heat. Thus the Iron Bacteria of 

 Winograwdski ' require ferrous carbonate for their life and deve- 

 lopment, oxidizing the same to oxide. This can be physiologi- 

 cally interpreted as a respiration process, the protoxide of the 

 resniration material becoming the oxide of respiration product. 



The Sulphur Bacteria are equally remarkable. Their cells 

 are distinguishable by containing from time to time granules of 

 amorphous sulphur. These organisms were formerly regarded 

 as causing the formation of sulphuretted hydrogen in sulphur 

 springs. 



Winograwdski - claims the reverse to be the case. They do 

 not produce sulphuretted hydrogen but consume it, burning it 

 partially first to sulphur, which deposits in the cell water, then 

 completely to sulphuric acid, which passes out and forms sul- 

 phates from the carbonates of the surrounding water. When no 

 more carbonates are present:, the combustion of sulphur to sul- 

 phuric acid ceases. Physiologically this is also a process of re- 

 spiration directed towards generating heat and energy ; sul- 

 phuretted hydrogen is the respiration material and sulphuric acid 

 the respiration product. 



(Olivier 3 does not agree with Winograwdski and De Rey 

 Pailhade^ claims the existence of a substance, philothion, in many 

 plants and animal tissues capable of converting sulphur in the 

 cold to sulphuretted hydrogen.) 



Certain nitrification ferments can be regarded as intra-cellular. 

 They may take up ammonia and give it off as nitrates, this pro- 

 cess ceasing as in the case of the Sulphur Bacteria, when no 

 more carbonates are present. 



We now come to the discussion of two ferments, the concomi- 

 tant actions of which have heretofore caused much confusion. 

 , Schloesing and Muntz were the first to observe nitrifying fer- 

 ments, but to Warrington and Winograwdski belongs the credit 

 of isolating the nitrous from the nitric ferment ; furthermore, the 

 striking discovery of a colourless organism, capable of existing 

 and performing its functions, in a medium totally devoid of or- 

 ganic material, and synthetically producing organic bodies inde- 

 pendent of sunlight. The importance of this discovery cannot 

 be over-estimated, 



Warrington^ succeeded in obtaining organisms from meadow 

 soil, cultivated in a solution of ammonium chloride and calcium 

 carbonate, which oxidized ammonia to nitrous acid, but had no 

 effect on nitrates. Assimilating the carbon of the carbon-dioxide, 

 they require no organic substance for sustenance. They obtain 

 from the oxidation heat of ammonia the necessary energy to 

 dissociate the carbon-dioxide. 



Winograwdski® obtained the same ferment employing i gr. 

 ammonium sulphate, i grm. potassium phosphate dissolved in 

 I litre Zurich water, to which he added basic magnesium car- 

 bonate. After inoculating the sterilized fluid with the nitrifying 

 agent every trace of ammonia disappeared the fifteenth day. He 

 describes this ferment as being an elongated ellipsoid, the 

 smaller diameter o "9 - i Mkr., the larger it ~ i "8 Mkr. The 

 organisms congregate about a piece of carbonate, cover it with 

 their gelatinous mass, and as the carbonate disappears the cells 

 take the shape thereof. 



(Although the two investigators do not quite agree as to the 

 morphological attributes of the ferment, Warrington arrived at 

 the same conclusions as Winograwdski.) 



Winograwdski'' has at last succeeded in isolating the ferment 

 which converts the nitrites into nitrates. He employed gela- 

 tinous hydrate of silica, impregnated it with a fluid containing 

 the cultivated nitrous ferment. This medium was next inocu- 

 lated with strongly nitrifying soil from Quito ; shortly after- 

 wards two different organisms formed respective colonies, one 

 of these was the one sought for. It was composed of irregularly 

 shaped rods, dissimilar to the nitrous ferment of the same soil. 

 He has since found this ferment in many other soils ; it is cap- 

 able of converting solutions of nitrites into nitrates. 



^ Bot Ztg., xlvi. 261. 



3 Cr. cvi. 1744- 



8 Chem. News, Ixiii. 296. 



7 A. J. P., V. 577 ; Cr. cxiii. 89. 



Bot. Ztg., xlv. 489, 513, 545, 569, 585, 

 Cr. cvi. 1683 ; evil. 43. 

 A. J. P., September 1890. 



NO. 1 198, VOL. 46] 



Strange to say the isolated ferment from Quito does n. 

 oxidize ammonia; it produced neither nitrites nor nitrates whci 

 sowed in ammoniacal fluids, easily nitrified by the nitroi 

 ferment. 



In normal soils the nitrate ferment only produces nitrate.-, 

 even in the presence of a large quantity of ammonia, which does 

 not retard the oxidation of the nitrites immediately after their 

 formation. 



Muntz ^ claims the existence of an ammoniacal ferment in 

 the soil which converts organic nitrogen into ammonia, pre- 

 paratory lo nitrification. 



Extra- Cellular Oxidation. 



In order to oxidize outside of the organisms, oxygen must be 

 evolved by an assimilation process. Assimilation as an oxidizing 

 cause, for conditions prevailing in the soil, has heretofore 

 received no significance, since the evolution of oxygen, according 

 to the generally accepted theories, depended upon light and 

 chlorophyll, consequently the produced oxidation could only 

 occur on the extreme outer surface. An exception to this here- 

 tofore unrestricted rule has been found by Engelmann as well 

 as one by Heraus. According to Engelmann,- Bacterium 

 photometricum sharply discriminates between lights of different 

 intensity and wave lengths. The influence of light upon the 

 bacteria is directly proportionate to the intensity. When the 

 intensity is suddenly decreased, the bacteria shoot backwards 

 with opposite rotation (the author calling this a terror motion), 

 consequently a well-defined illuminate<l spot in an otherwise 

 dark drop serves as a traip for these bacteria. They cannot 

 leave, since the terror motion causes them to move back into 

 the illuminated field as soon as they come to the dark outline. 



The mobile forms principally congregate in the ultra red rays, 

 i.e. physiologically in darkness, and in them as in the visible 

 parts of the spectrum in places closely corresponding to the 

 absorption bands of bacteriopurpurin. This constant ratio be- 

 tween absorption and photokinetic action clearly indicates that 

 the prime effect of light is equivalent to the carbon-dioxide dis- 

 sociating processes of plants containing chlorophyll. 



The bacteriopurpurin is a true chromophyll, inasmuch as it 

 converts the actually absorbed energy of light into potential 

 chemical energy. When lights of different colour were em- 

 ployed, the evolution of oxygen increased with the absorption 

 of light by the Purple bacteria. This shows that the power of 

 developing oxygen is not the specific property of a certain colour- 

 ing matter, as these organisms contain no chlorophyll. 



It is not surprising, therefore, that other organisms, either 

 coloured or uncoloured, be found to possess the property of 

 assimilating carbon in the absence of light and evolving oxygen. 

 Such a discovery has now been made — Hueppe* substantiating 

 a communication from Heraus that certain colourless bacteria 

 produce from humus and carbonates, in the absence of light, a 

 body closely resembling cellulose. Oxygen is liberated, but 

 remains unobserved, as it is immediately used to oxidize the 

 ammonia to nitric acid. 



The next question is : To which extent do the oxidizing organ- 

 isms partake in the oxidation phenomena actually taking place 

 in the soil ? "According to E. Wollny "• the oxidation of carbon- 

 dioxide is almost completely to be attributed to the activity of 

 small organisms, of which Adameiz ^ estimated that thei-e are 

 about 500,000 to I gr. soil. As in all such experiments, this 

 conclusion is based upon the fact that no evolution of carbon- 

 dioxide takes place, or is forced to a minimum, in a sterilized 

 soil under otherwise favourable conditions. 



Liberation of Combined Nitrogen. 

 This may take place during putrefaction under the greatest 

 possible exclusion of oxygen, or during decay in the presence of 

 oxygen. It does not necessarily occur in all cases, or may not 

 be observed owing to a reverse concomitant process, i.e., the 

 fixation of nitrogen. Nitrogen losses can be expected during 

 decay, on account of the action of the produced nitrous acid upon 

 the amidlike dissociation of humous bodies, as well as in the 

 formation of easily dissociable ammonium nitrites. A peculiar 

 case of the disappearance of available nitrogen exists in the re- 

 duction of nitrates, as noticed by Springer, " Gayon and 

 Dupetit, ^ and Deherain and Marquenne.^ 



^ Cr. ex. 1206. 



3 Ntf. Vers., Ix. 



5 Inaug. Diss., Leipsie, 



' Cr. xcv. 644, 



Bot. Ztg., xlvi. 661, 677, 693, 709. 

 ' LV. bt.. xxxvi. 197. 

 ' Amer. Chem. Jour., iv. 452-53. 



Bot., vii. 138. 



