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during immunity, septicaemia and in the normal state. Each 

 time the same bacteria which had been used to produce either 

 immunity or septicaemia were brought into contact with the 

 endothelium. 



The method of immunisation was as follows: to begin with 

 small quantities of killed bacteria were injected, intravenously 

 or subcutaneously, then followed injections with large quantities, 

 and the last injection was one with living bacteria. An exception 

 was made for the streptococci: only one big dose of bacteria 

 killed by heat at 6o° was injected. As a rule a certain stage of 

 immunity was reached after 10 days by this method. 



The degree of immunity was controlled either by NEISSER and 

 WECHSBERG'S method or by the phagocytic count. The condition 

 of septicaemia was arrived at by injecting fatal doses of living 

 bacteria, intravenously in rabbits, and by direct injections into 

 the heart in rats. 



The principle was to let the endothelium react on bacteria 

 in the absence of the blood. In order to attain this two methods 

 were followed. The first one was executed in this way: 



the carotid artery of a rabbit was prepared with as small 

 an incision as possible, a canula was tied into the vessel, and 

 the animal bled to death. In the meantime the jugular vein 

 was prepared and another canula tied into that vessel. This 

 canula is attached to a rubber tube, connected with an irrigator. 

 This irrigator contains warm physiological saltsolution. To exclude 

 the air the canula must be tied in, whilst the solution is flowing 

 out. A conical piece of glass tubing somewhere in the rubber 

 tube and filled with gauze prevents any particles which might 

 intervene with the constant flow, to enter into the canula. The 

 irrigator is elevated about 20 inches, and empties itself very slowly. 

 The canula in the carotis which at first produced red blood, slowly 

 changes its contents. The fluid coming forth from it shows less 

 and less colour. The wound through which the carotis and the 

 jugular vein were reached becomes wet again. If it starts leaking 

 badly, an arteryclamp is necessary. The fluid from the carotis- 

 canula ends by being quite clear, at the same time the mucous 

 membranes of the animal are nearly white. As a rule about 2 

 pints of salt water are wanted to wash out all the blood in 

 this way. To make sure the process is continued a little while 



