REPORT OF THE SECRETARY. 25 



tries with a central bureau in London, where reference cards are as- 

 sembled and published annually in 17 volumes covering each branch 

 of science. During the past year there were collected and classified 

 in the Smithsonian office and sent to London 12,386 cards of reference 

 to the scientific literature of the United States for the year 1914, be- 

 sides 14,027 references for the years 1906 to 1913, or an aggregate of 

 26,413 cards, making 345,349 references to American literature since 

 1901. 



Through a minute system of classification, the equivalent of a brief 

 digest of the subject contents of each paper, the International Cata- 

 logue places before students and investigators references to practi- 

 call}^ all the scientific literature of the world. 



On account of the necessarily high cost of the annual volumes sub- 

 scriptions to the series are limited as a rule to the most important 

 institutions and libraries, where, however, the catalogue is available 

 to everyone desiring to consult this work. 



As in all lines of scientific work, the European war temporarily in- 

 terferes with the finances and general work of the catalogue and the 

 amount of literature produced in most of the countries at war is 

 greatly curtailed. 



NATIONAL ZOOLOGICAL PARK. 



There was added to the collections in the National Zoological Park 

 during the past year a number of interesting animals, including 25 

 species not before represented there. The total accessions aggregated 

 498. The census of animals on hand Jime 30, 1915, was 1,397 indi- 

 viduals, representing 151 different species of mammals, 185 of birds, 

 and 22 of reptiles, as compared with 1,362 animals on hand July 1, 

 1914. The report of the superintendent of the park, on another page, 

 records a detailed systematic list of all the animals, numbering 629 

 mammals, 696 birds, and 72 reptiles. 



Every year since 1890, when the park was established, many speci- 

 mens have been received through the individual donations of those 

 interested in its growth. Forty-three such donors during the past 

 year contributed 60 animals. 



The total number of visitors was 794,530, an increase of about 

 60,000 over the year preceding, and the largest attendance in the his- 

 tory of the park. Among the visitors were 3,485 students from vari- 

 ous schools and classes on special visits to the park for educational 

 purposes. 



The superintendent notes among the improvements of the year the 

 construction of a cage and shelter house for pumas; and an out-of- 

 doors inclosure with a small shelter house for a band of 25 rhesus 

 monkeys which thrived there well throughout the winter. 



