474 SEROTHERAPY 



showing that perhaps 80 per cent, of adults have been infected with the 

 tubercle bacillus, whether or not they have clinical tuberculosis requiring 

 treatment. Moreover, in many advanced or acute cases of tuberculosis 

 the patients do not react, so that the result of a tuberculin test is never 

 absolute but always must be judged in the light of other findings. The 

 occurrence of a focal reaction is good presumptive evidence of an active 

 lesion. 



For children the cutaneous test has been chiefly used. This is per- 

 formed by abrading the cleansed skin of the forearm in two places 2 inches 

 apart through a drop of undiluted old tuberculin at each site; another simi- 

 lar abrasion is used as a control between the two; the two drops of tuber- 

 culin are carefully wiped off after ten minutes, allowing no tuberculin to 

 touch the control site. The reaction consists in a zone of redness, mark- 

 edly larger than that at the control site. This reaction reaches its height 

 in from twenty-four to forty-eight hours. After infancy an increasing 

 proportion of those who react are found to be free from clinical tubercu- 

 losis. The subcutaneous test is used more frequently on adults. A two- 

 hour temperature chart should be kept for two days preceding and two 

 days following each injection. To an adult in good condition 0.0002 mil 

 may be given as the initial dose, and if there is no reaction o.ooi mil and 

 then 0.005 m il may be tried. The doses should be at least three days 

 apart and if there is the slightest suggestion of a reaction in temperature 

 or symptoms the dose should be repeated, not increased. Children and 

 weak patients should receive smaller doses, but no very weak patient 

 and none with a fever should be subjected to the danger of a subcutaneous 

 test. A rise of temperature of iF. may be taken as a reaction, especially 

 if accompanied by changes at the site of the disease. This reaction 

 means, just as with the cutaneous test, only infection and not necessarily 

 clinical tuberculosis and owing to the danger of large doses, patients may 

 fail to react because, though sensitive to tuberculin, they are not sensi- 

 tive to doses small enough to be used safely. 



For treatment from o.oooooooi mil to o.oooooi mil may be used as 

 the initial dose, and not more than two doses a week should be given. 



LUETIN. Luetin is an extract of the killed cultures of several strains 

 of the Treponema pallidum, the causative agent of syphilis. 



When injected into the skin, luetin provokes no reaction in normal 

 individuals except a very small erythematous area at and around the point 

 of injection. In certain cases of syphilitic infection, a reaction occurs 

 -consisting of papules which may become pustules. When the reaction 

 takes the papular form, a large reddish indurated papule (usually from 

 7 to 10 mm. in diameter) makes its appearance in twenty-four to forty- 

 eight hours and slowly increases for four or five days, after which the in- 

 flammatory process begins to recede. The color of the papule gradually 



