Chapter 6

1. The degree of concentration of the solution is important. Nitrification always commences first in the weakest solution, and there is probably in the case of every solution a limit of concentration beyond which nitrification is impossible.

2. The temperature has great influence. Nitrification proceeds far more rapidly in summer than winter.

3. The presence or absence of light is important. Nitrification is most rapid in darkness; and in the case of solutions, exposure to strong light may cause nitrification to cease altogether.

4. The presence of oxygen is of course essential. A thin layer of solution will nitrify sooner than a deep layer, owing to the larger proportion of oxygen available. The influence of depth of fluid is most conspicuous in the case of strong solutions.

5. The quantity of nitrifying organism present has also a marked effect. A solution seeded with a very small amount of organism will for a long time exhibit no nitrification, the organism being (unlike some other bacteria) of very slow growth. A solution receiving an abundant supply of the ferment will exhibit speedy nitrification, and strong solutions may by this means be successfully nitrified, which with small seedings would prove very refractory. The speedy nitrification which occurs in soil (far more speedy than in experiments in solutions under any conditions yet tried) is probably owing to the great mass of nitrifying organisms which soil contains, and to the thinness of the liquid layer which covers the soil particles.

6. The rapidity of nitrification also depends on the degree of alkalinity of the solution. Nitrification will not take place in an acid solution; it is essential that some base should be present with which the nitric acid may combine; when all available base is used up, nitrification ceases.

It appeared of interest to ascertain to what extent nitrification would proceed in a dilute solution of urine without the addition of any substance save the nitrifying ferment. As urea is converted into ammonium carbonate in the first stage of the action of the ferment, a supply of salifiable base would at first be present, but would gradually be consumed. The result of the experiment showed that only one-half the quantity of nitric acid was formed in the simple urine solution as in similar solutions containing calcium and sodium carbonate. The nitrification of the urine had evidently proceeded until the whole of the ammonium had been changed into ammonium nitrate, and the action had then ceased. This fact is of practical importance. Sewage will be thoroughly nitrified only when a sufficient supply of calcium carbonate, or some other base, is available. If, instead of calcium carbonate, a soluble alkaline salt is present, the quantity must be small, or nitrification will be seriously hindered.

Sodium carbonate begins to have a retarding influence on the commencement of nitrification when its amount exceeds 300 milligrammes per liter, and up to the present time I have been unable to produce an effective nitrification in solutions containing 1.000 gramme per liter.

Sodium hydrogen carbonate hinders far less the commencement of nitrification.

Ammonium carbonate, when above a certain amount, also prevents the commencement of nitrification. The strongest solution in which nitrification has at present commenced contained ammonium carbonate equivalent to 368 milligrammes of nitrogen per liter. This hinderance of nitrification by the presence of an excess of ammonium carbonate effectually prevents the nitrification of strong solutions of urine, in which, as already mentioned, ammonium carbonate is the first product of fermentation.

Far stronger solutions of ammonium chloride can be nitrified than of ammonium carbonate, if the solution of the former salt is supplied with calcium carbonate. Nitrification has in fact commenced in chloride of ammonium solutions containing more than two grammes of nitrogen per liter.

The details of the recent experiments, some of the results of which we have now described, will, it is hoped, shortly appear in the _Journal_ of the Chemical Society of London.

Harpenden, July 21.

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ANILINE DYES IN DRESS MATERIALS.

By Professor CHARLES O'NEILL.

Twenty-eight years ago Mr. Perkin discovered the first of the aniline dyes. It was the shade of purple called mauve, and the chief agent in its production was bichromate of potash. This salt is not actively poisonous, and no one thought of attributing injurious properties to materials dyed with the aniline mauve. Next in chronological order came magenta red. It was first made from aniline by the agency of mercurial salts, and afterward by that form of arsenic known to chemists as arsenic acid. The fact that this at one time fashionable color was prepared by means of an arsenical compound was spread through the country in a very impressive manner by the great trial as to whether the patent was valid or not, all turning upon the expression in the specification of "dry arsenic acid," and the disputes of scientists whether this expression meant arsenic acid with or without water. The public mind had been for some time previously exercised and alarmed by accounts of sickness and debility caused by arsenical paper-hangings; it was, therefore, easy for pseudo scientists to create an opinion that the magenta dye must be also poisonous, and that persons wearing materials dyed with this color were liable to absorb arsenic and suffer from its action. Ever since there have been, at intervals, statements more or less circumstantial, that individuals have suffered from wearing materials dyed with some of the artificial dyes. At the present time these statements are emphasized by the exhibition at the Healtheries of models of skin diseases said to be actually produced by the wearing of dyed garments. Whether it be true or not that any form of skin disease has been produced by the wearing of dyed articles of clothing is simply a question of evidence, and there is evidence enough to show that individuals have experienced ill effects who have worn clothing dyed with artificial colors. But, as far as we know, there is an entire want of any evidence that will satisfactorily show that the inconvenience suffered by wearers of these dyed goods has been owing to the dyeing material. Years must elapse before chemists or physicians can hope to become thoroughly informed of the physiological action produced by the cutaneous absorption of the thousands of new products which the ingenuity and industry of technological chemists have made available for the manufacture of colors; they are also new to science, most of them very complex in their constitution, and so dissimilar to previously studied compounds used by the dyer, that it may be said we have nearly everything to learn concerning their action upon the human economy. With respect to dyed woolen and silk goods it is almost entirely a question as to the innocence or otherwise of the coloring matter itself, which in nine cases out of ten is an organic body containing no mineral matter of any sort, and not requiring the assistance of any mordant to enable it to dye. Considerations of arsenic, or antimony, or mercury existing in the dyed stuffs are absolutely excluded. In a few cases the dyestuff is a zinc compound, and zinc in small traces may possibly be fixed by the material, but this metal is not known to be actively noxious. Textiles made from fibers of animal origin do not require, and as a rule do not tolerate, the addition of any metal in dyeing with the artificial colors, and if the manufacture of the color require the use of a metal, such as arsenic, which by unskillfulness or carelessness is left in it when delivered to the dyer, the tendency of the animal fiber is to reject it.

But the case with regard to textiles made from vegetables fibers is quite different; upon materials made from cotton, flax, jute, or other fiber of the vegetable kingdom, the new aniline colors cannot be fixed without the assistance of other bodies acting the part of mordants. Some of these bodies are actively poisonous in their nature, and introduce a possible element of danger to the wearer of the dyed article. For many years, almost the only method of dyeing cotton goods with the aniline colors consisted in a preliminary steeping in sumac or tannic acid, followed by a passage in some suitable compound of tin, and subsequent dyeing in the coloring matter. Sumac and tin have been used for two hundred years or more as the dyer's basis for a considerable number of shades of color from old dye-stuffs; there never has been the least suspicion that there was anything hurtful in colors so dyed. Sumac or tannic acid, in combination with alumina, may be held to be equally inoffensive; now it is a fact that the great bulk of cotton goods are dyed with the aniline colors by the agency of these harmless chemicals. But of late years the dyers of certain goods, and the calico printers generally, have found an advantage in the use of tartar emetic, and other compounds of antimony, to fix aniline colors; besides this, some colors are fixed in calico printing by means of an arsenical alumina mordant; it need not be mentioned that antimony, as well as arsenic, is, when administered internally, an active poison in even small quantities, and that externally both are injurious under certain conditions. An alarmist would require nothing further than this statement to feel himself justified in attributing everything bad to fabrics so colored; but the practical dyer or calico printer knows that though he employs these poisonous bodies in his business, and that some portion of them does actually accompany the dyed material in its finished state, not only is the quantity excessively small, but that it is in such a state of combination as to be completely inert and innoxious. In the case of tartar emetic, it is the tannate of antimony which remains upon the cloth, a compound of considerable stability, and almost perfectly insoluble in water; in the case of a few colors fixed by the arsenical alumina mordant, the arsenic is in an insoluble state of combination with the alumina, in fact, the poisons are in the presence of their antidotes, and not even the most scrupulous manufacturer has any fear that he is turning out goods which can be hurtful to the wearer. Persons quite unacquainted with the process of dyeing are apt to think that goods are dyed by simply immersing them in a colored liquid and then drying them with all the color on them and all that the color contains; they do not know that in all usual cases of dyeing a careful washing in a plentiful supply of water is the final process in the dye-house, and that nothing remains upon the cloth which can be washed out by water, the color being retained by a sort of attraction or affinity between it and the fiber, or mordant on the fiber. Dyeing is not like painting or even the printing or staining of paper for hangings, where the vehicle and color in its entirety is applied and remains. It follows, therefore, that many chemicals used in dyeing have only a transitory use, and are washed away completely--such as oil of vitriol, much used in woolen dyeing--and that of others only a very minute quantity is finally left on the cloth, as is the case in antimony and arsenic in cotton dyeing and printing.

There is evidently among working dyers, as among all other classes, an unknown amount of carelessness, ignorance, and stupidity, from which employers are constantly suffering in the shape of spoiled colors and rotted cloth. It is not for us to say that the public may not at times have to suffer also from neglect of the most common treatments which should remove injurious matters from dyed goods; what can be said is, that if the dyeing processes for aniline colors be followed out with ordinary care and intelligence, it is extremely improbable that anything left in the material should be injurious to human health.--_Manchester Textile Recorder._

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CASE OF RESUSCITATION AND RECOVERY AFTER APPARENT DEATH BY HANGING.

By ERNEST W. WHITE, M.B. Lond., M.R.C.P., Senior Assistant Medical Officer to the Kent Lunatic Asylum; Associate, Late Scholar, of King's College, London.

The following case, from its hopelessness at the outset, yet ultimate recovery under the duly recognized forms of treatment, is of such interest as to demand publicity, and will afford encouragement to others in moments of doubt.

M.A. S----, aged fifty-three, was admitted into the Kent Lunatic Asylum at Chartham on Oct. 3, 1882, suffering from melancholia, the duration of which was stated to have been three months. She had several times attempted suicide by drowning and strangulation. She was on admission ordered a mixture containing morphia and ether thrice daily, to allay her distress. On Oct. 10 she attempted suicide by tying a stocking, which she had secreted about her person, round her neck. Shortly afterward, with similar intent, she threw herself downstairs. On Jan. 4, 1883, she attempted to strangle herself with her apron. On the 30th of November following, at 4 P.M. she evaded the attendants, and made her way to the bath-room of of No. 1 ward, the door of which had been left unfastened by an attendant. She then suspended herself from a ladder there by means of portions of her dress and underclothing tied together. A patient of No. 1 ward discovered her suspended from the ladder eight minutes after she had last seen her in the adjoining watercloset, and gave the alarm.

The woman was quickly cut down, and the medical officers summoned. In the interval cold affusion was resorted to by the attendant in charge, but the patient was to all appearances dead. The junior assistant medical officer, Mr. J. Reynolds Salter, M.B. Lond., arrived after about three minutes, and at once resorted to artificial respiration by the Silvester method. A minute or so later the medical superintendent and myself joined him. At this time the condition of the patient was as follows: The face presented the appearance known as facies hippocratica: the eyeballs were prominent, the corneæ glassy, the pupils widely dilated, not acting to light, and there was no reflex action of the conjunctivæ; the lips were livid, the tongue tumefied, but pallid, the skin ashy pale, the cutaneous tissues apparently devoid of elasticity. There was an oblique depressed mark on the neck, more evident on the left side; the small veins and capillaries of the surface of the body were turgid with coagulating blood the surface temperature was extremely low. She was pulseless at the wrists and temples. There was no definite beat of the heart recognizable by the stethoscope.

There was absolute cessation of all natural respiratory efforts, complete unconsciousness, total abolition of reflex action and motion, and galvanism with the ordinary magneto-electric machine failed to induce muscular contractions. The urine and fæces had been passed involuntarily during or immediately subsequent to the act of suspension. As the stethoscope revealed that but a small amount of air entered the lungs with each artificial inspiration, the tongue was at once drawn well forward, and retained in that position by an assistant, with the result that air then penetrated to the smaller bronchi. Inspiration and expiration were artificially imitated about ten times to the minute. In performing expiration the chest was thoroughly compressed. The lower extremities were raised, and manual centripetal frictions freely applied. In the intervals of these applications warmth to the extremities was resorted to.

About ten minutes from the commencement of artificial respiration we noticed a single weak spasmodic contraction of the diaphragm, the feeblest possible effort at natural respiration. Simultaneously, very distant weak reduplicated cardiac pulsations, numbering about 150 to the minute, became evident to the stethoscope. The reduplication implied that the two sides of the heart were not acting synchronously, owing to obstruction to the pulmonary circulation induced by the asphyxiated state. Artificial respiration was steadily maintained, and during the next half hour spasmodic contractions of the diaphragm occurred at gradually diminishing intervals, from once in three minutes to three or four times a minute.

These natural efforts were artificially aided as far as possible. At 5:45 P.M. natural respiration was fairly though insufficiently established, the skin began to lose its deadly hue, and titillation of the fauces caused weak reflex contractions. Flagellation with wet towels was now freely resorted to, and immediately the natural efforts at respiration were increased to twice their previous number. The administration of a little brandy and water by the mouth failed, as the liquid entered the larynx. Ammonia was applied to the nostrils, and the surface temperature was increased by warm applications and clothing. At 6 P.M. artificial respiration was no longer necessary. The heart sounds then numbered 140 to the minute, the right and left heart still acting separately. A very small radial pulse could also be felt. At 6:45 P.M. the woman was put to bed, warmth of surface maintained, and hot coffee and beef-tea given in small quantities.

Great restlessness and jactitation set in with the renewal of the circulation in the extremities. An enema of two ounces of strong beef-tea was administered at 10 P.M. The amount of organic effluvium thrown off by the lungs on the re-establishment of respiration was very great and tainted the atmosphere of the room and adjoining ward. The pupils, previously widely dilated, began to contract to light at 11 P.M. Imperfect consciousness returned at 5 P.M. the following day (Dec. 1), and about an hour later she vomited the contents of the stomach (bread, etc., taken on Nov. 30). Small quantities of beef-tea were given by the mouth during the night. At 9 A.M. air entered the lungs freely, and there were no symptoms of pulmonary engorgement beyond slight basic hypostasis; the pulse remained at 140, and the heart sounds reduplicated; she was semiconscious, very drowsy, in a state of mental torpor, with confused ideas when roused, and she complained of rheumatic-like pains all over her.

The temperature was 100.2°; the facial expression more natural; the tongue remained somewhat swollen and sore; she was no longer restless; she took tea, beef-tea, milk, etc., well; the functions of the secreting organs were being restored; she perspired freely; had micturated; the mucous membrane of the mouth was moist, and there was a tendency to tears without corresponding mental depression. The patient was ordered a mixture of ether and digitalis every four hours. On December 2 the pulse was 136, and the heart sounds reduplicated. The following day she was given bromide of potassium in place of the ether in the digitalis mixture. On the 4th the pulse was 126; reduplication gone. On the 6th the pulse was 82, and the temperature fell with the pulse rate. She was well enough to get into the ward for a few hours. Her memory, especially for recent events, was at that time greatly impaired. On the 12th she still complained of muscular pains like those of rheumatism. Apart from that, she was enjoying good bodily health.

A curious fact in connection with this case is that since this attempt at suicide she has steadily improved mentally, has lost her delusions, is cheerful, and employs herself usefully with her needle. She converses rationally, and tells me she recollects the impulse by which she was led to hang herself, and remembers the act of suspension; but from that time her memory is a blank, until two days subsequently, when her husband came to see her, and when she expressed great grief at having been guilty of such a deed. Her bodily health is now (June 30, 1884) more robust than formerly, and she is on the road to mental convalescence.

_Remarks._--The successful issue of this case leads me to draw the following inferences: 1. That in cases of suspended animation similar to the above there is no symptom by which apparent can be distinguished from real death. 2. That in artificial respiration alone do we possess the means of restoring animation when life is apparently extinct from asphyxia, and that, with the tongue drawn well forward and retained there by the hand or an elastic band, the Silvester method is complete and effective. 3. That artificial respiration may be necessary for two hours or more before the restoration of adequate natural efforts, and that the performance of the movements ten times to the minute is amply sufficient, and produces a better result than a more rapid rate. 4. That galvanism, ammonia to the nostrils, cold affusion, and stimulants by the mouth are practically useless in the early stage. 5. That on the re-establishment of the reflex function we possess a powerful auxiliary agent in flagellation with wet towels, etc. 6. That centripetal surface frictions and the restoration of the body temperature by warm applications aid recovery. 7. That the heart, if free from organic disease, has great power of overcoming the distention of its right cavities and the obstruction to the pulmonary circulation, although its action may for a time be seriously deranged, as evidenced by reduplication of its sounds. 8. That when the heart's action remains excessively feeble, and the right and left heart fail to contract synchronously, it would be justifiable to open the external jugular vein. 9. That during recovery the lungs are heavily taxed in purifying the vitiated blood, as shown by the excessive amount of organic impurities exhaled. 10. That restlessness and jactitation accompany the restoration of nerve function, and that vomiting occurs with returning consciousness. 11. That pains like those of rheumatism are complained of for some days subsequently, these probably resulting from the sudden arrest of nutrition in the muscles.

Chartham, near Canterbury.

--_Lancet._

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THE INVENTORS' INSTITUTE.