148 THE EXCITATION OF AMCEBOID MOVEMENTS 



increase as more alkaloid was absorbed; but such is 

 not the case. Moreover, this excitation is not caused 

 by poisons, such as nitrobenzol and prussic acid. The 

 possibility of the excitation being due to a death- 

 struggle is also precluded by the fact that if no 

 stain is employed the excited movements may be 

 watched for an hour. Death-struggles, as seen in 

 higher animals, do not usually last very long, and 

 always commence immediately before dissolution. The 

 excitation appears to be a specific one caused by 

 alkaloids, although we have seen a similar form of 

 excited movements, but not to the same extent, 

 caused by arsenic. 1 



As already mentioned, we have ascertained the 

 amounts of other alkaloids which cause maximum 

 excitation of leucocytes, and in finding out these 

 "doses" we have always used a similar jelly containing 

 no stain, and the temperature employed has been that 

 of the room in every case. The jelly was alkaline, as 

 it contained 5 units of alkali solution, and the alkaloids 

 were each used in a 1-per-cent solution, thus: To 

 5 cc. of coefficient jelly, 5 units of alkali solution, and 

 the amount whatever it is of alkaloid solution were 

 added, and the balance, up to the usual total of 10 cc., 

 was made with water. The jelly was then boiled, and 

 a film prepared from it in the usual way, fresh citrated 

 blood being used in each case. 



The following is a list of alkaloids which we have 

 tried on leucocytes, and the amount of each of them 



1 The effects of oxygen have been tried on leucocytes by bubbling the gas 

 through the jelly; but its action seemed to be negative. 



