158 



yet, the fullest measure of popular support and favorable atten- 

 tion. 



What has been the greatest weakness of our best publicity 

 work? It seems to me, the fact that we have been too optimistic, 

 that we have been telling people that getting rid of mosquitoes was 

 an easy matter, and that big results were going to be noticeable 

 in too short a time. The experience of one or two rainy summers 

 shows that we have not progressed as far as we perhaps thought 

 in the beginning, and it is well to be cautious about making too 

 great claims about the elimination of mosquitoes for some time 

 as yet. 



In closing, let me put particular emphasis on the big argument 

 for mosquito work, that we ought to hammer on in any bit of 

 publicity work, that is, the economic argument, the fact that suc- 

 cessful anti-mosquito work means a small outlay for a big in- 

 crease in wealth. People are going to give us their biggest and 

 best support when they know that for every dollar they are spend- 

 ing in mosquito work they are going to get $100.00 back. 



Pre:sident Darnai,!, — We will call for the next paper, ''The 

 Local Malaria Problem," by Ulric Dahlgren, of Princeton. 



Mosquitoes and Malaria in Princeton. 



BY UI.RI.C DAHIvGREN, PH.D., ASSOCIATE: PROFESSOR OE BIOL^OGY 

 IN PRINCETON UNIVERSITY. 



We do' not know whether our malaria was a new world dis- 

 ease or was brought to this country by settlers from the old 

 world. As there are several kinds of malaria in most localities, 

 it seems probable that at least some of our varieties were brought 

 over by the first or some of the early emigrants. These different 

 kinds depend on the different species of protozoan parasites that 

 produce them. The parasites get into our blood and, multiply- 

 ing vastly, they bore into and break up vast numbers of the red 

 blood cells, producing the well-known chills and fevers and other 

 symptoms that so many are familiar with. 



How do they get into our blood? One way only is known. 

 A mosquito bites us and first she injects some fluid into our 



