64 Report of the President 



or driving wells, the varying physical qualities of water as to 

 color and turbidity, the micro-organisms which grow in reser- 

 voirs and cause unpleasant tastes and odors, the sources of 

 pollution of water supplies, with relief maps illustrating certain 

 historic epidemics, the methods in use for purifying water on 

 a municipal scale and in the home, and the gains to human life 

 and health which have been attained in cities of New York 

 State by the substitution of pure water supplies for polluted 

 ones. The most difficult part of the work, the preparation of 

 the models and relief maps, is well advanced, and it is hoped 

 that the exhibit may be installed during the spring. 



A series of models of bacteria is also under preparation, 

 which will illustrate recent discoveries in regard to the struc- 

 ture of these minute organisms, and will include all the more 

 important bacterial enemies of man, such as the tubercle 

 bacillus, the typhoid bacillus, the plague bacillus and the 

 spirillum of cholera, with killed and preserved colonies show- 

 ing their actual growth. 



The department has prepared for the Department of Public 

 Education an album of large photographs illustrating the ways 

 in which communicable disease spreads, and how it can be 

 avoided, for use by classes in the public schools. It is hoped 

 that this album may help in some degree in the vital and 

 difficult task of popularizing knowledge as to the laws of indi- 

 vidual health. 



The Museum of Bacteria which we are establishing is the 

 only one of its kind in the United States. The collection of 

 bacterial cultures has grown very rapidly during the year. 

 We have now under cultivation 479 cultures, representing 322 

 different types, and forming what is probably the most com- 

 plete collection of bacteria in existence, with the single excep- 

 tion of the Krai collection at Vienna; 577 cultures have been 

 sent out from the laboratory to 53 different institutions in the 

 United States and Canada, representing an earnest of a unique 

 and important service to American bacteriological teaching 

 and research. The resources of the department laboratory 

 are severely taxed, however. It has been so far impossible to 

 begin a systematic study of our cultures, for which the collec- 

 tion offers such unusual facilities, and it is hoped that further 



