proceedings: biological society 257 



the discovery of hemolysis by normal and immune serums from the 

 early observation following transfusion by Landois in 1875, through 

 Pfeiffer's phenomenon of bacteriolysis in 1899, Bordet's discovery of 

 of complement in 1899, and Borclet and Gengou's discovery of com- 

 plement fixation in 1901 to the practical application of the latter 

 phenomenon as utilized by Wassermann in 1905 and by later workers 

 in the diagnosis of syphilis, glanders, Malta fever, dourine, tuberculosis, 

 infectious abortion, etc. The graphic conceptions of amboceptor, 

 complement, antigen, and fixation as understood by Ehrlich, and as 

 understood by Bordet, were illustrated by movable models. The 

 action of hemolytic amboceptors and complement on blood cells of the 

 ox and of the sheep was demonstrated by test tube mixtures, and some 

 positive and negative results in complement fixation were exhibited. 



The last paper of the regular program was by D. L. Van Dine: 

 A study of malarial mosquitoes in their relation to agriculture. Mr. 

 Van Dine said that the Bureau of Entomology is making a study of the 

 relation of malaria to agriculture and of the malaria-bearing mosquitoes, 

 on a plantation in the lower Mississippi valley where typical conditions 

 as regards malaria and plantation operations occur. The object is 

 to devise measures for prevention of malaria which will apply practi- 

 cally to farming conditions. Lines of work include determination of the 

 manner in which malaria operates in reducing farm profits, of the rel- 

 ative efficiency of Anopheles to act as transmitting agent and their 

 distribution, of behavior of each species under known conditions of 

 environment, and consideration of preventative measures which involve 

 control of mosquito hosts. Solution centers around prevention of 

 malaria among tenants, since it has been shown that the direct loss to 

 planters occurs through lost time and reduced efficiency in labor. 

 Detailed study was made of tenants, their relation to the plantation, 

 their habits, and the prevalence of malaria among them, the conclusion 

 being that it will be more practical to control the mosquito than the 

 human host. 



One measure of prevention consists in the favorable location of ten- 

 ants' houses, requiring information on habits of flight, food, and 

 breeding of the mosquitoes. Where drainage is impracticable, sur- 

 face water must be rendered unsuitable for Anopheles development. 

 Food requirements and natural checks to larval development are being 

 studied, the Bureau of Fisheries cooperating in the study of the re- 

 lation of fish to mosquito development. 



Anopheles quadrimaculatus, A. punctipennis, and A. crucians were 

 the species studied. A. quadrimaculatus is the common house-fre- 

 quenting species of that region, A. crucians occurs in very limited 

 numbers, and A. punctipennis is more restricted in its house habits 

 but is common in nature. The work thus far has dealt almost entirely 

 with A. quadrimaculatus, but following the demonstration of tertian 

 and estivo-autumnal malaria in A . punctipennis by King in cooperation 

 with Bass it will be expanded to include this species. The study includes 

 the habits of mosquitoes under low temperature conditions; also the 



