190 



NATURE 



[June 25, 



■sation of sensory impulses in the spinal cord, as taught by 

 Brown- Sequard. 



The experiments which I have performed exhibit the following 

 principal points of interest : — 



(i) Return of associated movements after complete destruction 

 of the cros5ed pyramidal tract below the lesion. 



(2) That all sensory impulses do not decussate in the cord — in 

 fact, they appear to show that certain sensory impulses, e.g. 

 touch, the muscular sense, and localization in space, pass chiefly 

 up the same side, painful impressions up both sides. A peculiar 

 condition known as " allochiria " occurs after hemisection. 



(3) The vaso-motor disturbances are on the same side as the 

 lesion, and consist of vaso-dilation, swelling of the foot, and 

 redness with rise of temperature of the skin of the foot (as 

 compared with the opposite side), and fall of temperature in 

 the popliteal space on the side of the lesion, due, no doubt, to 

 paralysis of the muscles, 



(4) The degenerations above and below the lesion are limited 

 to the same side when the injury is perfectly unilateral. There 

 are certain facts connected with the degenerations which serve to 

 show the origin and course of certain long and short tract fibres. 



(5) Stimulation of the cortex cerebri on^both sides some weeks 

 or months after '^\r hemisection had been performed gave, as a 

 rule, results which showed that the block in the spinal cord 

 produced by the hemisection still existed, although there had 

 been a very complete return of associated movements. 



(6) In one case ablation of the leg area on the same side as 

 the lesion in the spinal cord was performed many months after- 

 wards. 



Chemical Society, May 21.— Prof. A. Crum Brown, F.R.S., 

 President, in the chair. — The following papers were read: — 

 Bromo-derivatives of betanaphthol, by H. E. Armstrong and 

 E. C. Rossiter. The authors have completed the study of the 

 compounds formed on brominating betanaphthol, to which they 

 have referred in two previous notices (Chem. Soc. Proceedings, 

 1889, p. 71 ; 1890, p. 32). In the present paper they give 

 directions for preparing tri- and tetra-bromobetanaphthol, and 

 summarize the properties of the bromobetanapthols. The entire 

 product of the action of bromine in excess on betanaphthol, has 

 been carefully examined without any substance having been dis- 

 covered which afifords i : 2 : 3-bromophthalic acid on oxidation ; 

 the discrepancy between the authors' observations and the earlier 

 experiments of Smith and Meldola, therefore, yet remains to be 

 discovered, — The action of nitric acid on naphthol derivatives 

 as indicative of the manner in which nitration is effected in the 

 case of benzenoid compounds generally : the formation of 

 nitro-keto-compounds, by H. E. Armstrong and E. C. Rossiter. 

 The chloro- and bromo-derivatives of betanaphthol when warmed 

 with nitric acid are converted into derivatives of betanaphtho- 

 quinone ; but the formation of these compounds is preceded by 

 that of an unstable intermediate compound. These intermediate 

 compounds, when carefully heated, are converted into deriva- 

 tives of betanaphthaquinone. Thus, when nitric acid is added 

 to dibromobetanaphthol, suspended in acetic acid, a clear solu- 

 tion is obtained which, after a short time, deposits a crystalline 

 substance ; if quickly evaporated by filtration, this product is 

 almost colourless, but it decomposes when kept, becoming yellow. 

 This compound, when treated with alkali, yields bromonitro- 

 naphthol. Bromobetanaphthol, in like manner, yields Oi-nitro- 

 betanaphthol, and the tri- and tetra-bromo-derivatives yield di- 

 and tri-bromonitrobetanaphthol. The authors are of opinion 

 that the intermediate compounds in question are nitro-bromo- 

 keto-derivatives, and that their formation afifords evidence that 

 the elements of nitric acid first become added to the bromo- 

 naphthol, thus : — 



Br NOo 

 Br 



OH 



OH 



The theory that the formation of such addition- compounds pre- 

 cedes that of nitro-compounds generally, appears to afford a 

 satisfactory explanation of a number of well-known facts which 

 hitherto have remained unexplained. The non-production of 

 nitro- compounds from paraffins and their derivatives appears as 

 the natural consequence of the inability of paraffins to form 

 addition-compounds. The theory affords a simple explanation 

 of the formation of nitro-derivatives of phenols on nitrating 

 hydrocarbons, for if the addition-compound lose H.NOo instead 

 of H.OH a phenol would result, thus — 



H.OH 



OH 



HO . NO. = 



H.NO., 



-f HNOo 



An agent which would tend to withdraw water from the addi- 

 tion-compound would increase the production of nitro-compound 

 and diminish that of phenol ; and it is known that when a mixture ; 

 of nitric and sulphuric acids is used, there is less of the phenol 

 derivative produced than when nitric acid alone is employed. 

 A compound like the addition-compound of benzene, represented 

 above, would obviously be unstable, and prone to undergo 

 oxidation ; hence the explanation of the large amount of nitrous 

 fume produced on nitrating benzene. The non-production of 

 resinous matters when sulpho-acids are treated with nitric acid 

 to form the corresponding nitro-compound by displacement of 

 the SO3H group by NO2 is also elucidated by the authors' 

 theory ; the addition-compound formed in such a case would 

 very readily break up into sulphuric acid and the nitro-deriva- 

 tive. — A new method of preparing nitro-derivatives, and the 

 use of nitrogen dioxide as a nitrating agent, by H. E. Arm- 

 strong and E. C. Rossiter. The authors find that the unstable 

 compounds formed by the addition of the elements of nitric acid 

 to the bromo-derivatives of betanaphthol yield nitro-derivatives 

 of the naphthol on treatment with alkali, a bromine atom be- 

 coming displaced by NOg. On treating the addition-compound 

 with sulphurous acid, a practically theoretical yield of the nitro- 

 naphthol is obtained ; this method appears to be of general 

 application. The authors have been naturally led to study the 

 action of nitrogen-dioxide, NOo, on unsaturated compounds of 

 various kinds, in the hope of obtaining addition-compounds 

 which by loss of HNO2 would pass over into nitro-derivatives 

 of the substances treated. They find that such addition-com- 

 pounds are obtained, and on treatment with alkali and reducing- 

 agents yield nitro-compounds. Thus betanaphthol yields 75 per 

 cent, of its weight of nitro-betanaphthol ; alphanaphthol be- 

 haves similarly. Phenol yields ortho- and para-nitrophenol. 

 The authors propose to study the action of nitric acid and 

 nitrogen dioxide on unsaturated compounds generally from 

 the point of view indicated in this and the previous note. — 

 Nitrification, by R. Warington. The first section of the parper 

 describes early experiments, showing the existence of an agent 

 producing only nitrites, and the means of separating it from 

 soil. Successive cultivation in ammoniacal solutions made per- 

 manently alkaline with disodium carbonate was found to be a 

 certain method of obtaining a purely nitrous agent. Pasture soil 

 yielded the nitrous agent more readily than arable soil. The 

 nitrous organism was isolated by the dilution method. Cultiva- 

 tions were made in an ammonium chloride solution with calcium 

 carbonate. The nitrous organism oxidizes ammonia to nitrous 

 acid, and has no effect on nitrites. It produces nitrous acid in 

 solutions of asparagine, milk, urine, and urea. Grown in broth 

 containing calcium nitrate, it does not reduce the nitrate to 

 nitrite. It requires no organic matter for its nutrition, and is 

 apparently capable of assimilating carbon from acid carbonates. 

 The presence of either calcium or sodium acid carbonate dis- 

 tinctly favours nitrification ; neutral sodium carbonate greatly 

 hinders nitrification. The nitrous organism occurs as nearly 

 circular corpuscles, which stain deeply. It also occurs as oval 

 cocci, the ends occasionally more or less truncated. The re- 

 mainder of the paper deals with the nitric organism. The 

 results show that the nitric organism develops freely in inorganic 

 solutions containing potassium nitrite, phosphates, &c., espe- 

 cially if supercarbonates are present. IMonosodium carbonate, 

 1-4 grams per litre, exerted a very favourable influence ; 6 grams 

 per litre, a retarding influence. Disodium carbonate greatly 

 hinders the action. The nitric organism produces neither 

 nitrites nor nitrates in ammoniacal solution. In the absence of 



