312 Messrs Hanlcin and Kanthack, On the fever produced [Feb. 22, 



the numbers of leucocytes present in the blood, and the degree of 

 ' bactericidal power ' possessed by the serum derived from it. 



The following is a short summary of our observations : 



(1) Methods employed. The microbe was grown in calves-foot 

 bouillon for fourteen days. The culture fluid was then sterilized 

 by heating in an autoclave to 115° C. for a quarter of an hour. 

 Of the turbid liquid thus obtained \ to f cc. was injected into the 

 lateral ear vein of a rabbit by means of a Koch's syringe. The 

 temperature of the rabbit was taken in the usual way every half- 

 hour, and when desired the animal was killed by cutting the 

 carotid artery under antiseptic precautions. The blood was received 

 into a sterilized centrifuge tube and was centrifugalised as soon 

 as clotting had taken place. By this means a large quantity of 

 serum can be obtained within a few minutes of the death of the 

 animal. 



(2) The rise of temperature. Almost always such an injection 

 was followed by a rise of temperature of 1 to 2| degrees Centigrade. 

 A temperature of 41 , 4°C. was the highest that we have hitherto 

 observed. The temperature generally rises quickly and within an 

 hour after the injection may be two degrees above the normal. 

 The maximum temperature is reached in 1^ to 2| hours after 

 injection. The fall is far more gradual, but the temperature has 

 generally returned to the normal within six hours of the injection. 



(3) Effect of the injection on the number of leucocytes present 

 in the blood. Soon after the injection the number of leucocytes 

 present falls to a fraction of the normal. Within an hour of the 

 injection the larger leucocytes with lobed nuclei may have dimin- 

 ished to so great a degree that several preparations have to be 

 examined before one of them can be seen. The smaller white 

 blood corpuscles however, consisting of one spherical deeply-staining 

 nucleus and a trace of protoplasm (= lymphocyte), are not affected 

 to so great an extent. Often scarcely any decrease in their 

 number can be observed. At about the period of the acme of the 

 fever a slight increase in the number of leucocytes is generally 

 to be seen, so that almost as many are present as in the blood 

 of a normal rabbit. At a later stage, when the fever has nearly 

 passed off, a great increase in the number of leucocytes is always 

 met with. In the majority of cases this increase is quite sudden. 

 In one case for instance a preparation of blood taken 4|- hours 

 after injection showed scarcely any of the larger leucocytes. A 

 similar preparation made 4§ hours after injection, showed a well- 

 marked leucocytosis. Five hours after the injection so many 

 leucocytes were present that 40 to 50 could often be counted 

 under the microscope in a single field of view. The increase affects, 

 for the most part, the larger leucocytes with lobed nuclei. As a 



