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longer. In some cases, especially when a high pressure was 

 wanted, it grew necessary to bandage the abdomen of the animal, 

 to prevent the fluid from assembling in the vessels of the 

 abdomen. After this wash-out the suspension of the bacteria 

 in physiological salt that had to be used for the experiment 

 was poured into the irrigator and instead of the pure saltsolution 

 this suspension was led into the vessels. The quantity was such, 

 that when the irrigator had emptied itself it might be supposed 

 that the whole of the animal was filled up. After that the 

 canula's were taken out, and the abdominal cavity was opened. 

 A piece of the mesenterium, of the spleen and the liver were 

 taken out and brought into formol or aceton. The whole animal 

 was placed into the incubator and with intervals of 8 hours 

 pieces of mesenterial vessels and organs were taken out and 

 prepared for further examination. 



This method was not applicable to white rats. The carotid 

 artery and the jugular vein are too small to allow a canula to 

 be brought in. The method used here was to lay bare the heart 

 with as little damage as possible and then to pull the heart up 

 with a small hooklet. The left ventricle was opened with a short 

 incision, and the animal bled to death. Now a special canula is 

 wanted. It must be fairly thin and have a swollen end, more 

 or less in the form of an olive. This is forced into the opening 

 made in the ventricle, and if it is of the right size the heartmuscle 

 contracts over it and holds it tight. To this canule is attached 

 the usual arrangement of the irrigator. After a while the venae 

 of the atria swell enormously. This is a sign that the fluid has 

 passed through the whole body. These veins are cut open and 

 the washing and filling up with an emulsion of bacteria takes 

 place in the usual way. Here too pieces of vessels and organs 

 are taken out at regular intervals. The whole animal is kept 

 in an incubator. All the material taken from these animals was 

 brought into paraffin and sections were made in the usual way. 

 Some trouble was experienced in the staining method. With a 

 modification and complication of Weigert-KChne's method 

 the best results were obtained. This is as follows: 

 i. Hansen's haematoxylin 5 minutes. 



2. Wash in water. 



3. In slightly alcaline water 24 hours. 



19 



