HI 



ANTISEPTICS. 



ANTISEPTICS. 



390 



bid fair to render every other superfluous : these are the chlorides of 

 soda and of lime. In these preparations chlorine is combined with the 

 bases in such a way as to be susceptible of decomposition, and is 

 evolved with more or leas rapidity according to the ingredients or 

 impurities it meets with in the air. The most common of these im- 

 purities is carbonic acid gas, which is produced both by the respiration 

 of living animals, and by the decomposition of their bodies when dead. 

 Another product of putrid animal matter is ammoniacal gas, which 

 generally unites with the carbonic acid, and forms carbonate of 

 ammonia, the presence of which may be recognised by the pungency 

 of the air impregnated with it, which affects both the eyes and the 

 organ of smell Now, it is interesting to remark, that carbonic acid 

 gas has the greatest tendency to unite with the soda or the lime, and 

 to liberate the chlorine. Again, chlorine decomposes ammoniacal gas 

 by abstracting the hydrogen from the nitrogen, and forming hydro- 

 chloric or muriatic acid. One example of its beneficial action will 

 prove its utility. Air was passed through blood, which had been left 

 to putrefy for eight days ; being then passed through a solution of the 

 chloride of lime, carbonate of lime was deposited, and the air was 

 rendered inodorous and completely purified. These agents can 

 only be productive of benefit within a limited range of atmosphere, 

 yet they may be employed successfully to purify the air of hospitals, 

 sick-rooms, ftc. 



Quick-lime, or charcoal recently prepared, has been employed to 

 absorb fetid and noxious exhalations, and though inferior to the chlo- 

 rides, may be used in some cases, such as when the patient cannot bear 

 the smell either of the chloride of soda or of lime. Nitrate of lead is 

 extremely serviceable when put into night-tables or water-tlosets. 

 When the matter of contagion is supposed to be attached to woollen 

 or cotton clothes, we may expose these to a high temperature, 212 

 of Fahrenheit, for some hours, by which it will be dissipated. 



An equally important means of warding off the effects of exposure 

 to a contagious atmosphere, is to put the body in a posture of defence 

 by strengthening it, and regulating the general health. Increasing the 

 vital force of the system renders it less susceptible of being acted upon 

 by impure air; hence nourishing food and tonic medicines may be 

 regarded as indirectly antiseptics. It is a wise precaution not ti> visit 

 the sick without previously taking food. But useful as a supply of 

 proper nourishment is, still it is of inferior efficacy, an a protective 

 means, compared with ventilation and cleanliness, as is demonstrated 

 by the instructive fact, that in Great Britain, we were 200 years later 

 in getting rid of pestilence than of famine. Most of the medicines 

 which were formerly termed antiwpties are either tonics or refrigerants : 

 of which cinchona bark may serve as an example of the first clam, and 

 the mineral and vegetable acids, as dilute sulphuric acid, and tartaric 

 acid or citric acid of the second. Tonic antiseptics cannot be employed 

 with propriety or safety at the beginning of fevers or inflammatory 

 complaints, but in many diseases a period arrives when they may be 

 usefully administered. The period when their employment becomes 

 safe requires the nicest discrimination on the part of the medical 

 attendant; and too numerous are the instances where their premature 

 employment has rekindled the disease which might otherwise speedily 

 have subsided. We are, however, justified in having recourse to them 

 at an earlier period in those diseases which we know to have a great 

 tendency to lead rapidly to the death of some part ; such as in the 

 malignant or putrid sore-throat of scarlet fever ; or in continued fever 

 of a very typhoid character. 



The refrigerating antiseptics may be beneficially used from a very 

 early period of inflammatory diseases, especially of the young and robust : 

 in such diseases as scurvy (', e. sea-scurvy), they surpass all other 

 remedies. 



As the operations of nature in regard to organised matter seem to 

 consist in reducing to their elementary state each individual, or part, 

 when it ceases to li ve, and in reconstructing others, it forms an inter- 

 esting and important subject of investigation to inquire in what way 

 the former of these may be prevented, when it is desirable to preserve 

 the whole or a part of organised matter from putrefaction ; by what 

 means can the tendency to putrefaction be so modified, that the result 

 of it, though leading to the formation of a substance having a very 

 different character, shall yet be of a kind which may be preserved for 

 a longer period, than the original substance; and how the process 

 o< putrefaction may be rendered a useful, instead of a noxious, 

 operation. 



There are many substances which, when added to animal matter, 

 prevent for a longer or shorter time their decomposition, such as salt- 

 petre (nitrate of potass), and common salt (chloride of sodium), which 

 last is supposed to act by abstracting the element* of water : certain it 

 in that meat is rendered by salting much drier, harder, less easily 

 digested, and consequently less nourishing. [AirriscoRBTmcs.] Many 

 aromatic substances have a similar power of preventing putrefaction for 

 a time. They were extensively employed in embalming in ancient as 

 well as modern times, as the Egyptian mummies prove. Oils and 

 rtsinous substances long resist putrefaction, and preserve other sub- 

 staaoes from it ; bitumen, naphtha, and empyreumatic oils are examples 

 of this. Russia leather, which is dressed with the empyreumatic oil of 

 the birch, not only does not become mouldy, but also preserves the 

 book" which are bound with it. The process of decomposition i* greatly 

 hastened by the agency of fungi, such as those which cause mouldiness, 



and the more formidable destroyers which occasion the dry-rot. The 

 fungi which cause mouldiness are generally prevented from developing 

 themselves by the presence of some aromatic oil ; and the others which 

 occasion the dry-rot in timber may be prevented from developing them- 

 selves by the process invented by Mr. Kyan. This consists in combining 

 the albumen of the wood with bichloride of mercury (corrosive subli- 

 mate), which it converts into the protochloride, in the same way that 

 animal albumen combines with, and converts into the protochloride, 

 the same compound [ALBPMEN] ; the wood is thus rendered insus- 

 ceptible of the attacks of the fungi. Fungi often attack and destroy 

 the cereal grains, particularly wheat : the worst of these namely, the 

 Uredo frftida (pepper-brand) may be prevented from farther developing 

 itself by steeping the seeds for twelve hours in lime-water. 



The collections of entomologists and botanists suffer much from the 

 depredations of insects. Those which infest collectisns of insects may 

 be driven away by placing camphor in the cases, or by introducing a 

 solution of bichloride of mercury into tne blood-vessels of larger 

 animals previous to stuffing them. " Dried plants, for botanical speci- 

 mens, may be preserved from the attacks of the ptima fur by applying 

 to them, when perfectly dry, a solution of bichloride of mercury, of the 

 strength of two drachms to a pint of rectified spirit of wine, to which 

 a little camphor has been added. It must be applied to the whole 

 specimen by means of a camel-hair pencil. 



ANTISEPTICS are the means of preventing those changes in 

 organised matter which are comprehended under the term putre- 

 faction, and are used in the preparation of PRESERVED FOOD. 



All organised substances do not piitrefy with equal rapidity, nor 

 under all circumstances. Decomposition goes on fastest in substances 

 which contain nitrogen, and most slowly in those which are richer in 

 carbon : hence, animal matters putrefy quickly ; vegetable, especially 

 of a woody texture, gradually. The conditions necessary for putre- 

 faction to take place are, the presence of air, of a certain temperature, 

 and moisture. If any one of these be excluded, the process is pre- 

 vented. The moisture may either be external, or it may consist of the 

 fluids of the body itself. The bulk of the animal frame is made up of 

 fluids, which must either be dissipated by heat, abstracted by some 

 chemical process, or rendered solid by a very low temperature, if we 

 wish to preserve any animal substance in the state most near that of 

 its natural constitution. 



The modes of preserving food are either natural or artificial. The 

 natural modes comprehend those which effect this end by abstracting 

 or excluding one or more of the chief agents heat, moisture, and air ; 

 the artificial, comprehend those methods of preparation or mixture 

 which produce some chemical change in the substance. 



1. Abstraction of heat. The presence of heat is essential to the 

 exertion of those chemical affinities which take place during decom- 

 position, or constitute the process ; abstracting it therefore checks or 

 suspends them. Most articles of food keep better in cold than in warm 

 weather. When the heat has been so completely abstracted that 

 the juices are frozen (that is, become solid), the preservation of the 

 substance is more effectually accomplished. Indeed they may thus be 

 preserved for many years, perhaps ages. On this principle the Russians 

 preserve their poultry, which they kill in October, and pack in tubs 

 with interlayers of snow. The markets of St. Petersburg are supplied 

 with veal brought from a great distance in this state, as well as with 

 whole hogs, sheep, and fish. The Canadians preserve their provisions 

 in the same way. 



A precaution is necessary in thawing the preserved provision : for 

 this end, they should always be put into cold water first. This meets 

 with an example in the case of persons buried in the snow, when 

 recovery is much more likely to be brought about by plunging the 

 individual into cold water, than by placing him in a warm bed. 



This method of preserving food is not applicable to vegetables, but 

 when these are frozen they should also be first put into cold water. 



2. The abstraction of moisture by heat is employed in drying fish 

 and other animal substances, .as beef, bacon, &c. ; though in these th 

 rapid tendency to putrefaction makes the employment of a certain 

 quantity of salt, &c., necessary, along with the drying, unless the pro- 

 cess be carried on with great rapidity, which may be effected by a high 

 tempcratxire and a free circulation of air. Hence, in many places, 

 where turf or wood is burnt, hams are hung within the wide kitchen 

 chimney. Drying is also employed for the preservation of vegetable 

 substances, such as grain, hay, &c. It is by this means that botanists 

 preserve plants to form a hortus siccus, or herbarium, and herbalists 

 many plants for medical use ; but for this purpose a high temperature 

 should never be applied, as it dissipates their active principles. 



3. The exclusion of sources of oxygen gas constitutes another means 

 of preventing or checking putrefaction ; and aa the atmospheric air in 

 the most common source of oxygen, we shall limit our remarks to the 

 means of excluding it. The effect of such exclusion is very great. 

 Reaumur varnished some eggs, and found that at the end of two years 

 they were yet capable of producing chickens ; and Bomare mentions 

 an instance where three eggs were inclosed within the walls of a church 

 in Lombardy, and when found at the end of 300 years they had not 

 lost their flavour. Lime-water is the best medium in which to place 

 eggs for long keeping. But more valuable articles than eggs are pre- 

 served by this means, and in a condition nearly equal to their fresh 

 state. We allude to the method of preserving animal food and vege- 



