324 TEAGUE, 



tetanus antitoxin, in the Widal and precipitin tests, in vaccine tlierapy, 

 etc. Likewise, the study of tiie hypersensitive reaction, though still in 

 its infancy, has already demonstrated that the rare instances of sudden 

 death following the injection of antitoxin and the rashes, joint pains and 

 fever occurring during the course of serum treatment, are in no wise due 

 to the antitoxin as such but to the vehicle of the antitoxin and are hence 

 nothing more or less than the expression of the hypersensitive reaction 

 to the proteins of the horse serum. 



Another important acquisition to practical medicine resulting from the 

 study of hypersensitiveness, is von Pirquet's cutaneous reaction which was 

 first announced in May, 1907. Von Pirquet had observed that if the 

 skin of a tuberculous patient was scarified and moistened with a drop of 

 Koch's old tuberculin, within from twelve to forty-eight hours an urticaria- 

 like swelling or a papule surrounded by a reddened area appeared. His 

 technique consisted in placing a drop of old tuberculin on the skin of the 

 forearm which had been previously cleansed with ether and in scraping 

 away a small portion of epidermis beneath the di'op by a boring motion 

 with the point of a scalpel. A bit of cotton was then placed in the 

 tuberculin and left for ten minutes. Instead of a scalpel he later used 

 a special instrument with a chisel-like point for removing the epidermis. 

 Others have made a short superficial incision with a sharp knife, care 

 being taken not to draw blood. A control scarification without tuberculin 

 is made on the same arm for comparison. In the case of a positive reac- 

 tion a slight reddening appears in about twelve hours and the swelling 

 and redness reaches its maximum in from twenty-four to forty-eight 

 hours lasting four or five days or longer; whereas the swelling due to a 

 slight mechanical injury disappears in a day or two. 



Very soon after von Pirquet made known the discovery of his cutane- 

 ous reaction, both Wolff-Eisner and Calmette announced results obtained 

 by dropping a diluted tuberculin into the conjunctival sack of tuberculous 

 patients. The reaction that follows this procedure has become known as 

 the ophthalmoreaction, though in reality it is a conjunctival reaction and 

 the eye itself is in no way concerned. Calmette thought that the 

 glycerine of the old tuberculin was irritating and hence precipitated the 

 tuberculin with alcohol, and dissolved the precipitate in water. However, 

 later workers have found that in the dilutions in which it is used (one- 

 half to 1 per cent), the old tuberculin is entirely satisfactory. 



Another modification of the skin reaction was suggested by Moro,^ 

 who prepared an ointment of equal parts of lanolin and old tuberculin 

 and simply rubbed it into the skin over an area about 5 centimeters in 

 diameter. The positive reaction was indicated by the appearance of 

 papules and vesicles in the treated area. 



^Munch. med. Woe. (1908), 55-1, 216. 



