UNIVERSITY OF CALIFORNIA PUBLICATIONS 



ZOOLOGY 



Vol. 20, No. 9, pp. 235-242 April 12, 1922 



THE MICRO-INJECTION OF P\RAMAECIUM 



CHAS. WM. REES 



The development of the technique of isolation and micro-injection 

 bj' Barber (1914) and of micro-dissection and micro-injection by 

 Chambers (1918) and Taylor (1920) is of fundamental importance. 

 Barber applied this technique to studies in bacteriology ; Chambers to 

 studies of the physical changes that occur in living protoplasm, and 

 Taylor demonstrated the presence of conductile fibers in Euplotes. 

 The present paper is a report of some studies of the effect of a nema- 

 tode toxin on Paramaecium. The results of feeding Paramaecvimi 

 on Ascaris toxin are here contrasted with those of injecting this toxin 

 into the living cjiioplasm. 



The work was done under the direction of Dr. Charles A. Kofoid 

 of this laboratory and Dr. Walter R. Bloor of the Department of 

 Biochemistry. An attempt was made to induce transmissible changes 

 in the stock of Paramaecium. At first, the ciliates were fed on solu- 

 tions and suspensions of the ground up body wall, of the reproductive 

 organs, and of the digestive tract of Ascaris from the pig. The 

 ciliates were also placed in diluted solutions of the body fluid of 

 Ascaris. The results in all these tests were negative in so far as toxic 

 symptoms or other noticeable effects are concerned. Paramaecium 

 thrived -in all the solutions as well as or better than in the controls. 

 An attempt was then made to get more concentrated extracts of the 

 toxins by repeating the work of Shinuimura and Fujii (1917). 



Shimamura and Fujii extracted from Ascnris a proteose toxin 

 which the}' named askaron. The toxin was obtained as follows. The 

 worms, preserved in alcohol, were dried and pulverized. The fats 

 and lipoids were extracted with ether and alcohol, and the fat free 



