SPECIFIC BACTERIAL REACTIONS 187 



at 60° C. for an hour in a water-bath, preserved in 

 0.5 per cent, phenol and standardized with the dark- 

 field microscope, so that forty to one hundred dead 

 treponemata occupied the average field. To this 

 preparation Noguchi assigned the name luetin, and 

 has recommended it as a valuable diagnostic aid, 

 superseding even the Wassermann reaction in certain 

 forms of syphilis. The technic of the test consists 

 in sterilizing a small area of skin of both arms, using 

 alcoholic sublimate solution. Intradermically, in one 

 arm, with a syringe having a very fine needle, 0.05 of 

 a cubic centimetre of a control suspension is injected; 

 in the opposite arm a similar quantity of luetin. 



Normal or negative reactions consist of a small 

 erythematous and occasionally a papular formation, 

 not attended with pain or itching sensation, occurring 

 in 24 hours, and disappearing usually in 48 hours and 

 always in 72 hours, even if papular. No indm*ation 

 results, although yellowish pigmentation due to ecchy- 

 mosis is commonly seen. 



Positive reactions assume three forms : ( 1 ) papu- 

 lar, (2) pustular and (3) torpid, and are character- 

 ized by the formation, a day or two after inoculation, 

 of a large, reddish papule usually five to ten millime- 

 tres in diameter (Plate IV) . A hyperamic zone fre- 

 quently surrounds the papule. The inflammatory 

 process increases and extends for the next three or 



