178 THE MICHIGAN ACADEMY OF SCIENCE. 



medium, we must construct a fluid more favorable to the trypanosome 

 than the blood itself. 



In conclusion it is a pleasure to acknowledge the support received for 

 this investigation from the Board of Directors of the Rockefeller In- 

 stitute for Medical Research. 

 Ward J. MacNeal, Ph.D., 



Fellow of the Rockefeller Institute for Medical Research, 

 Hygienic Laboratory, University of Michigan, 

 Ann Arbor. 



