150 TOXINES AND ANTITOXINES. 



At first the vibriones showed vigorous increase within the capsule, but 

 soon they assumed other forms and then no longer increased ; they did not 

 die, however, but could still be cultivated months afterwards, on nutrient 

 media. Passed through the body of an animal after intraperitoneal injec- 

 tion they again yielded cultures of a high degree of virulence. 



They then endeavoured to obtain this poison also from culti- 

 vations of the vibriones thus made virulent. Old cultures have 

 relatively little toxic action, and they, therefore, used quite 

 young cultivations of two to twenty-four hours to three or four 

 days' growth. 



These when filtered had an average toxicity of O'S c.c. per 100 grms. of 

 animal. The addition of serum to nutrient liquids increased the degree 

 of toxicity and also the development of a torula form in the cultivation. 



The poison thus obtained was also stable when boiled, but was 

 soon rendered inactive by air and light. When hermetically 

 sealed up it kept for a long time. Alcohol and ammonium 

 sulphate did not precipitate it. It behaved in a manner 

 analogous to Ransom's poison. By injection of increasing doses 

 it was possible to produce an antitoxic immunity, which although 

 greater than that of normal serum, was yet exceedingly insignifi- 

 cant compared with that of diphtheria and tetanus antitoxines. 

 In the most favourable case 1 c.c. neutralised six times the 

 lethal dose ! In this respect its behaviour is the very opposite 

 of Pfeiffer's bactericidal antiserum, obtained by means of im- 

 munisation with dead vibrio cells, which is devoid of any 

 neutralising effect upon the toxine. This is an argument against 

 the view that the dead cells contain any appreciable amount of 

 immunising toxine, since otherwise this, when liberated, would 

 necessarily show its power of forming an ti toxine. 



COURMONT and Do YON 1 also obtained a soluble poison that 

 could be filtered ; it had an exceedingly small toxic effect, the 

 lethal dose for a rabbit being 4 c.c. (!). It produced hypothermia 

 and hsemorrhagia, also paralysis and peripheral neuritis. It 

 was extremely sensitive to the influence of light and air. Culti- 

 vations sterilised at 50 C. proved somewhat more poisonous. 



HAHN, 2 on the other hand, employing Buchner's method of trituration 

 and expression at a pressure of 4 to 5 atmospheres, isolated from quite 

 young cultivations, a cholera plasmine, in the form of a yellowish-brown 

 liquid, which when injected in doses of 0'5 to 0*6 c.c. protected guinea-pigs 

 after eight days against ten times the lethal dose. Particularly interesting 



1 Courmont and Doyon, " Effets de la toxine choler.," Arch, de Phys., 

 xxviii., 785, 1896. 



2 Hahn, ' ' Immunisierungs- u. Heilversuche mit den plasmat. Zellsaften, 

 &c.," Munch, med. Woch., 1897, 1344. 



