REPORT OF THE SECRETARY 17 
work were in press. Miss Frances Densmore, a collaborator of the 
Bureau, submitted three papers on Indian music and a complete bibli- 
ography covering 50 years of study of American Indian music. ‘The 
Bureau issued one Annual Report, one Bulletin, two volumes of the 
Handbook of South American Indians, and one publication of the 
Institute of Social Anthropology. 
Lnternational Hachanges.—The International Exchange Service is 
the official agency of the United States for the exchange of govern- 
mental and scientific publications between this country and all other 
countries. During the war shipments to many countries were neces- 
sarily suspended; but during the past year most of these shipments 
have been resumed, and accumulated material being held at the Insti- 
tution was reduced from 3,512 boxes to 1,109. The number of pack- 
ages passing through the exchanges totaled 540,502, which included 
3,117 boxes shipped from the Institution, an increase of 2,184 over the 
previous year; the total weight of the material handled was 472,299 
pounds. ‘The average weight of the individual packages was nearly 
double that of the year before, indicating that institutions are sending 
out some of the material held up by the war. 
National Zoological Park.—During the war years, because of short- 
age of personnel, maintenance of buildings and grounds was neces- 
sarily neglected to some extent. Although the return to prewar main- 
tenance standards has been hampered by the difficulty of recruiting 
trained personnel, nevertheless the past year witnessed a perceptible 
improvement in general conditions throughout the establishment. 
The Park urgently needs new buildings to replace the remaining 
antiquated structures still being used to house animals, and prelimi- 
nary planning has been discussed with the Public Works Adminis- 
tration for construction of these buildings when conditions justify 
such work. ‘The number of visitors for the year showed a marked 
increase over the previous year, owing to the removal of the wartime 
ban on pleasure driving and to the general increase in civilian travel. 
The total number of visitors was 2,372,337, an increase over the fiscal 
year 1945 of 265,253. Although the number of rare or unusual ani- 
mals has naturally decreased somewhat under wartime conditions, the 
reduction is largely offset by an increase in number of the commoner 
kinds. Rarities gradually began to come in again during the year, 
and it is anticipated that normal growth in this respect will now be 
resumed. At the close of the year the population of the Zoo num- 
bered 2,553 individual creatures, representing 701 different species. 
Astrophysical Observatory.—Final tabulation was made of the 
solar-constant values for the calendar year 1945. A new vacuum 
bolometer, designed at the Observatory, will eliminate gradual loss 
