CONTAGION. 



429 



first appearance of the hectic symptoms, the urine is 

 high coloured, and deposits a copious braiuiy red 

 sediment. The appetite, however, is not greatly im- 

 paired ; the tongue appears clean, the mouth is usu- 

 ally moist, and the thirst is inconsiderable. During 

 the exacerbations, a florid, circumscribed redness ap- 

 pears on each check ; but at other times the face is 

 pale, and the countenance somewhat dejected. At 

 the commencement of hectic fever, the belly is usu- 

 ally costive ; but in the more advanced stages of it, 

 a diarrhoea often conies on ; and this continues to 

 recur frequently during the remainder of the disease ; 

 colliquative sweats likewise break out, and these al- 

 ternate with each other, and induce vast debility. In 

 the last stage of the disease, the emaciation is so 

 great, that the patient has the appearance of a walk- 

 ing skeleton ; his countenance is altered, his cheeks 

 are prominent, his eyes look hollow and languid, his 

 hair tails on", his nails are of a livid colour, and much 

 incurvated, and liis feet are affected with oedematous 

 swellings. To the end of the disease, the senses re- 

 main entire, and the mind is confident and full of 

 hope. Those who suffer under it are seldom appre- 

 hensive or aware of any danger; and persons la- 

 bouring under its most advanced stage often flatter 

 themselves with a speedy recovery, and form distant 

 projects under that vain hope. Some days before 

 death the extremities become cold. In some cases a 

 delirium precedes that event, and continues until life 

 is extinguished. 



The morbid appearance most frequently to be met 

 with on the dissection of those who die of phthisis, is 

 the existence of tubercles in the cellular substance of 

 the lungs. These are small tumours, which have the 

 appearance of indurated glands, are of different sizes, 

 and are often found in clusters. Their firmness is 

 usually in proportion to their size, and, when laid 

 open in this state, they are of a white colour, and of 

 a consistence nearly approaching to cartilage. Al- 

 though indolent at first, they at length become hv- 

 fiamed, and, lastly, form little abscesses or vomicaj, 

 which, breaking and pouring their contents into the 

 bronchia, give rise to a purulent expectoration, and 

 thus lay the foundation of phthisis. Such tubercles 

 or vomicae are most usually situated at the upper and 

 back part of the lungs ; but, in some instances, they 

 occupy the outer part, and then adhesions to the 

 pleura are often formed. When the disease is partial, 

 only about a fourth of the upper and posterior part 

 of the lungs is usually found diseased ; but, in some 

 cases, life has been protracted till not one twentieth 

 part of them appeared, on dissection, fit for perform- 

 ing their function. A singular observation, confirm- 

 ed by the morbid collections of anatomists, is that 

 the left lobe is much oftener affected than the right. 



The diet, in this disorder, should be of a nutritious 

 kind, but not heating, or difficult of digestion. 

 Milk, especially that ot the ass ; farinaceous vege- 

 tables ; acescent fruits ; the different kinds of shell- 

 fish ; the lichen islandicus, boiled with milk, &c., are 

 of this description. Some mode of gestation, regu- 

 larly employed, particularly sailing, warm clothing, 

 removal to a warm climate or to a pure and mild air, 

 may materially concur in arresting the progress of 

 the disease in its incipient stage. With regard to 

 urgent symptoms, requiring palliation, the cough may 

 be allayed by demulcents, but especially mild opiates 

 swallowed slowly ; colliquative sweats by acids, par- 

 ticularly the mineral ; diarrhoea by chalk and other 

 astringents, but most effectually by small doses of 

 opium. 



CONTAGION, (contagio ; from contango, to meet 

 or touch each other.) This word properly imports 

 the application of any poisonous matter to the body 

 through the medium of touch. It is applied to tlie 



action of those very subtile particles arising from 

 putrid substances, or from persons labouring under 

 certain diseases, which communicate the diseases to 

 others ; as the contagion of putrid fever, the effluvia 

 of dead animal or vegetable substances, the mias- 

 mata of bogs and fens, the virus of small pox, lues 

 venerea, &c., &c. The principal diseases excited by 

 poisonous miasmata are, intermittent, remittent, and 

 yellow fevers, dysentery and typhus. The last is 

 generated in the human body itself, and is sometimes 

 called the typhoid fames. Some miasmata are pro- 

 duced from moist vegetable matter, in some unknown 

 state of decomposition. The contagious virus of the 

 plague, small-pox, measles, chincough, cynanche 

 maligna, and scarlet fever, as well as of typhus and 

 the jail fever, operates to a much more limited dis- 

 tance through the medium of. the atmosphere than 

 the marsh miasmata. Contact of a diseased person 

 is said to be necessary for the communication of 

 plague ; and approach within two or three yards of 

 him for that of typhus. The Walcheren miasmata 

 extended their pestilential influence to vessels rid- 

 ing at anchor, fully a quarter of a mile from the 

 shore. 



The chemical nature of all these poisonous effluvia 

 is little understood. They undoubtedly consist, how- 

 ever, of hydrogen, united with sulphur, phosphorus, 

 carbon, and azote, in unknown proportions and un- 

 known states of combination. The proper neutral- 

 izers or destroyers, of these gasiform poisons are, 

 nitric acid vapour, muriatic acid gas, and chlorine. 

 The two last are the most efficacious, but require to 

 be used in situations from which the patients can be 

 removed at the time of the application. Nitric acid 

 vapour may, however, be diffused in the apartments 

 of the sick without much inconvenience. Bed- 

 clothes, particularly blankets, can retain the conta- 

 gious fames, in an active state, for almost any length 

 of time. Hence they ought to be fumigated with 

 peculiar care. The vapour of burning sulphur or 

 sulphurous acid is used in the East against the 

 plague. It is much inferior in power to the other 

 antiloimic reagents. 



There does not appear to be any distinction com- 

 monly made between contagious and infectious dis- 

 eases. The infection communicated by diseased per- 

 sons is usually so communicated by the product of 

 the disease itself; for instance, by the matter of tiie 

 small-pox ; and therefore many of these diseases are 

 infectious only when they have already produced sik.h 

 matter, but not in their earlier periods. In many of 

 them, contact with the diseased person is necessary 

 for infection, as is the case with the itch, syphilis, 

 canine madness ; in other contagious diseases, even 

 the air may convey the infection, as in the scarlet 

 fever, the measles, the contagious typhus, &c. In 

 this consists the whole difference between the fixed 

 and volatile contagions. 



A real infection requires always a certain suscep- 

 tibility of the healthy individual ; and many infec- 

 tious maladies destroy, forever, this suceptibility of 

 the same contagion in the individual, and, accord- 

 ingly, attack a person only once, as the small-pox, 

 measles, &c. Other contagious diseases do not pro- 

 duce this effect, and may, therefore, repeatedly attack 

 the same person, as typhus, itch, syphilis, and others. 

 Sometimes one contagious disease destroys the sus- 

 ceptibility for another, as the kine-pox for the small- 

 pox. In general, those parts of the body which are 

 covered with the most delicate skin, are most sus- 

 ceptible of contagion; and still more so are wounded 

 parts, deprived ot the epidermis. Against those con- 

 tagious diseases which are infectious through the 

 medium of the air, precautions may be taken by 

 keeping tit the greatest possible distance from the 



