Properties of an Antityphoid Serum obtained from the Goat. 549 



endotoxin. To obtain this low antitoxic value in the horse a period of two 

 years was apparently necessary. » 



The typhoid cell juices employed in my experiments were prepared as 

 follows : Virulent typhoid bacilli were cultivated on nutrient agar in Eoux 

 bottles for 18 hours at blood heat. The growth was brushed off and washed 

 with distilled water in a centrifuge for half an hour. The bacilli were then 

 triturated at the temperature of liquid air in the grinding pot already 

 described by Eowland and myself.* The time allowed was 30 minutes 

 per gramme of bacilli. The mass was taken up in 1/1000 solution of caustic 

 potash, and centrifuged for two hours. The supernatant fluid was pipetted 

 off, and represented a 10-per-cent. extract of the ground mass. This was 

 treated with chloroform vapour for half an hour. The juices obtained under 

 these conditions were sterile and toxic on intravenous injection into the test 

 animals employed. The endocellular toxins obtained in this manner are 

 unstable bodies, and the juices rapidly decrease in toxicity. The experiments 

 with kept juices did not indicate that their injection would lead to any 

 marked tolerance for fresh and markedly toxic juices ; the probabilities 

 were against this easier and less risky method of procedure. Eesort was 

 accordingly made to the use of fresh and acutely toxic juices, which 

 contained on an average 10 to 12 milligrammes of solid matter per cubic 

 centimetre. The fresh juices on intravenous injection were acutely toxic 

 for the goat. The first goat died after the injection of 1 c.c, whilst 1/10 c.c. 

 killed several animals. In two instances 1/20 c.c. killed within 12 hours. 

 Death was preceded by profuse diarrhoea and collapse. Where death did not 

 occur, the injection of 1 /20 c.c. was followed by illness and diarrhoea, and 

 1/30 c.c. rendered certain animals ill, but with less acute symptoms. It was 

 obvious that the intravenous injections would have to be carefully carried 

 out to avoid unduly depressing or killing the animals. 



A goat after receiving 1/20 and 1/10 c.c. cell juice died, whilst another, after 

 the injection of doses of 1/20, 1/10, 1/2, and 1 c.c. at intervals of seven days, 

 died within four hours after receiving the last injection. The indication, it 

 appeared to me, was to start with small sublethal doses, and to raise them 

 very gradually at duly spaced intervals. One injection weekly proved to be 

 the safest procedure, and in the later experiments the same dose was 

 repeated until it failed to produce toxic symptoms in the animal. A higher 

 dose was then given and the process repeated. This method proved 

 successful, as the animals became tolerant to otherwise fatal doses of the 

 toxins. 



In the experiments here recorded the antiendotoxic action of the serum 

 * ' Centralblatt f. Bakter.,' vol. 34, No. 7, 1903. 



