VENOMS, TOXINS, ANTIBODIES 353 



sunlight. An exposure to diffuse daylight for several weeks or months 

 might be expected to produce inactivation. Jacobsohn also used a 

 different test: the "reaction precoce" (Marmorek's phenomenon); his 

 paper should be consulted for details. 



Ultra-violet radiation was used by Hausmann, Neumann, and Schu- 

 berth (77), and was found to inactivate tuberculin in dilute aqueous or 



o 



saline solution (0.1 to 10 per cent, in l}^ to 2 hr.) ; only light of X < 3250 A, 

 approximately, was effective. 



No experiments appear to have been made with X-rays, but Fabre 

 and Ostrovsky (52, 53) appear to have demonstrated a reduction in the 

 severity of the symptoms induced in tuberculous guinea pigs when 

 irradiated instead of unirradiated "necrotuberculin" (Ostrovsky) was 

 used. (See page 348 for certain critical reservations needful in the case 

 of these papers.) 



Wassermann antigen usually consists of a more or less modified 

 extract of luetic organs or of beef or other heart muscle. It is an excep- 

 tionally ill-defined material. Stiner and Abelin (154) appear to have 

 been the first to report inactivation of syphilitic antigens by ultra-violet 

 radiation. A few years later the effect of intense ultra-violet irradiation 

 (quartz-mercury-arc lamp, 220 volts, 3 amp., at 7 cm., the temperature 

 being kept close to 0°C.) on various antigens was reported in a preliminary 

 way by Friedberger and Scimone (67), and in more detail by Friedberger 

 and Shiga (68). Both luetic-liver and guinea-pig-heart extracts were 

 photosensitive, the latter only slightly; 40 hr. irradiation — a huge dose — 

 was required to inactivate the former. Addition of cholesterol protected 

 both, the latter being then not perceptibly labile. Another antigen was 

 "completely stabile." 



The antigen used by Brann (24) was not found to be affected by the 

 ultra-violet light from a 200- volt, 6-amp. Kromayer lamp at 0.5 to 1.0 

 cm. in 11^4 hr. This irradiation is short compared with that used by 

 Friedberger et al., and Brann also used cholesterinized beef-heart extract 

 which, according to these authors, is relatively insensitive. Under these 

 conditions the discrepancy of results is to be anticipated. 



Brann was also unable to detect any effect from X-rays (4 to 13 " E D " 

 — presumably erythema doses) or from suspension in a small volume of 

 antigen of a capsule containing 20 to 24.6 mg. of RaBr. 



Bacterial Antigens. — Welch (162) and Megrail and Welch (118) 

 have reported that the antigenic properties of tetanus toxin and of toxic 

 protein-free filtrates from bouillon cultures of bacteria of the colon- 

 typhoid group are somewhat more stabile under ultra-violet irradiation 

 (from special "cored" carbons) than are the concomitant toxic princi- 

 ples. In the first case it was possible to prepare an atoxic antigen; 

 in the latter case the toxic principle was inactive after 40 min., but the 

 antigenic principle, which sensitizes the skin to subsequent intravenous 



