SERUM THERAPY 641 



broth ; he now prefers a mixture of meat extract and ascitic fluid. After 

 incubation the growth is filtered. 



Macerate 500 grams of fresh minced veal for a few hours in a litre of warm water : 

 add 2 or 3 grams of gelatin at will, but no salt. Heat to 105 C. for half an hour. 

 Filter, concentrate to one-fourth its original volume and sterilize. To 25 parts of 

 this mixture add 75 parts of ascitic fluid. 



The gonococcus must be acclimatized to the medium by growing successively in 

 broth containing one-fourth then one- half of its volume of ascitic fluid. After 

 acclimatization the resistance and the toxigenic capacity of the organism increase. 

 The medium should be sown with a young 2 or 3 days- old culture on rabbit serum ; 

 the organism will remain alive in the liquid for 6 weeks. 



Twelve hours after sowing the medium is cloudy and the surface is covered with 

 a creamy pellicle ; later the fluid becomes clear, the growth being deposited as a 

 greyish viscous precipitate throwing out prolongations which float. 



The toxin content is at its maximum after the culture has been incubating for 

 3-4 weeks at 37 C. 



Properties. The toxin has all the properties of the diastases. It is pre- 

 cipitated from filtered cultures by strong alcohol and sulphate of ammonium. 

 It is soluble in glycerin. It can be heated to 65 C. for 15 minutes without 

 undergoing any change, but between 65 and 75 C. its properties are altered 

 and at 75-80 C. it is soon destroyed. It does not dialyse through parchment. 



The gonotoxin is very toxic to laboratory animals though they are immune 

 to the gonococcus itself. 



Sub- cutaneous or intra-peritoneal inoculation of 12 c.c. of the toxin will some- 

 times kill guinea-pigs though generally it is necessary to inoculate 510 c.c. of toxin 

 intra-peritoneally to produce a fatal result in these animals. Sub-cutaneous inocula- 

 tion in guinea-pigs and rabbits is followed by the formation of an abscess which 

 soon becomes the seat of secondary infections. The injection of toxin into the 

 pleural cavity of a rabbit produces a purulent but sterile effusion. 



Gonotoxin injected intra-cerebrally in doses of 0*002 c.c. kills guinea-pigs in 4-6 

 hours. Smaller doses are not fatal but lead to a high degree of immunity so that 

 the animal can resist further in tra- cerebral inoculations. Large doses of toxin 

 inoculated sub-cutaneously on several different occasions produce an immunity 

 against intra- cerebral inoculation. 



In man, a distinct urethritis is produced by injecting 2 c.c. of a 1 in 10 

 dilution of toxin into the fore part of the urethra and leaving it there for 

 2 or 3 minutes. 



3. Serum therapy. Agglutination. Vaccination. 



Goats which have been treated with large doses of gonotoxin inoculated 

 into the sub-cutaneous cellular tissue yield an antitoxic serum (De Christmas). 



A mixture of toxin and antitoxic serum is harmless. Neutralization does not 

 occur immediately but takes 3-4 hours : at 15 C. one-half of a cubic centimetre 

 of the serum neutralizes 10 c.c. of the toxin. 



If injected alone into the brain before the toxin, the serum protects the animal 

 for 3 days against an intra- cerebral inoculation of toxin, but if inoculated after 

 the toxin it has neither prophylactic nor therapeutic properties. 



Injected sub-cutaneously or into the veins or peritoneal cavity in large doses 

 (1-5 c.c.) the serum has prophylactic properties provided that the inoculation of 

 toxin be not made until after an interval of 48 hours. 



Vanned also prepared a rabbit serum which had therapeutic properties 

 against the gonococcus toxin and agglutinated the organism in dilutions of 

 1 in 200 to 1 in 400. 



Rogers and Torrey immunized sheep by intra-peritoneal inoculation. 

 Cultures heated to 65 C. for half an hour were used for the first inoculations, 

 then living cultures. The serum agglutinated the organism and according 



2s 



