PRINCIPLES OF VETERINARY SURGERY 443 



twenty-four to thirty-six hours, stiffness of the inoculated 

 member that spreads over the entire body and causes a typi- 

 cal tetanus. Knud Faber demonstrated that the tetanic poi- 

 son is very active, that intraveneous injections lead to imme- 

 diate generalized tetanus, that its ingestion is harmless and 

 that it is destroyed by heating at a temperature of 65°. He 

 advances the opinion that the toxin is a soluble product that 

 closely approaches diastases, an albuminoid substance re- 

 sembling diphtheritic poison, — a venom and not an alkaloid. 

 Tizzoni and Cattani, Villard and Vincent and Rouget in 

 1891 and 1892 continued arid completed this study. 



PREPARATION OF TETANUS TOXIN.— To prepare 

 the toxin a medium is made of neutral or alkaline, pepton- 

 ized, salted, fresh beef bouillon to which a small amount of 

 gelatine is added. Considerable quantities, — flasks of two 

 litres, — are used, and the cultures are left in the incubator 

 for eighteen to twenty days. The poison (toxin) is dissolved 

 in the bouillon.- By filtration through porcelain, the dissolved 

 toxin is separated from the bacilli. In this manner a very 

 toxic liquid, free from germs, is obtained. The liquid must 

 not be exposed to air, light nor heat. Its activity is then in- 

 creased by inoculating it with a new tetanic colony which 

 will develop well in the environment where the first genera- 

 tion has already lived. A dose of 1-150 of a cubic centimeter 

 of the liquid of the first generation will kill a cavy. The liquid 

 of the second generation after having. been in the incubator 

 another eighteen days, kills by a dose of 1-500 of a cubic cen- 

 timeter. 



The third generation is only possible by adding a small 

 quantity of new bouillon (20 c.c. per 350 c.c). If filtered after 

 sixteen days in the incubator a dose of i-iooo of a c.c. will kill 

 a cavy, and 1-100,000 c. c. will kill a mouse. The quantity of 

 real toxin contained in this small amount of liquid is trifling. 

 A cubic centimeter of the liquid evaporated in a vacuum 



