PREFACE Xlll 



In July, 1906, I left the navy and proceeded to 

 Egypt, having received an appointment there in the 

 Public Health Department. Sir Horace Pinching, 

 the Director-General, permitted me to continue the 

 researches, and it was during^ the ensuing year that 

 the phenomena of achromasia and liquefaction of the 

 cytoplasm of leucocytes were investigated together with 

 some of the laws concerning the diffusion of substances 

 into cells. In January, 1907, I accidentally discovered 

 the excitation of amoeboid movements caused by 

 atropine, for, as will be described in the chapter relative 

 to this phenomenon, I was in reality trying to poison 

 the cells with the alkaloid. 



In October, 1907, Sir Horace Pinching, my chief, 

 having retired, I w^as treated in such a manner by 

 Mr. W. P. Graham, the new Director- General of the 

 Public Health Department, that I was forced to leave 

 the Egyptian Government Service in December, 1907. 

 Mr. Graham objected to my doing scientific work dur- 

 ing my spare time, and also prevented my continuing 

 the mosquito campaigns which I had started, as he 

 apparently did not believe in them. This treatment 

 stopped may researches for the time being, and was the 

 cause of considerable delay in accomplishment of this 

 work. I was enabled, however, to complete my investi- 

 gations into the cause of achromasia by Dr. Marc 

 Armond- Ruffer, C. M. G., who came to my rescue and 

 temporarily gave me an appointment in the Quarantine 

 Department at Suakim in February, 1908. Here I 

 was also able to devise the technics for "measuring the 

 lives of leucocytes." 



