INTRODUCTION 



The appearance of the tenth full issue seems a good occasion to look back 

 into the past and to realize that the first issue started in 1949 with a total of 

 about 700 individual collaborators working in 250 institutes of 30 different 

 countries. In the present issue there are listed about 1700 collaborators in 

 687 institutes of 52 countries. The efforts to increase further the coverage of 

 the Service will be continued. 



Again, no essential alterations have been made in the general arrangement of 

 the periodical. Two short sections, however, have been cancelled. One is the 

 "Supply and Demand Service for laboratory animals", which was already 

 omitted from the Supplement to the ninth issue (1962). The reasons for can- 

 celling this section, are, firstly, that other international organizations are taking 

 over the task of supplying data on the availability of laboratory animals, and 

 secondly, that the data published in this section were considered to be highly 

 incomplete. The other cancelled section is that on "New technical methods in 

 developmental biology". The data published in this section were also consider- 

 ed very incomplete, and moreover were partly out of date at the moment of 

 publication. 



New contacts have been established with Sierra Leone (Africa), Iraq, and 

 the Philippines. The contacts with Spain, with the U.S.S.R., and with several 

 Middle-European countries have been markedly extended (cf. List of Institutes, 

 page 185 ff.). 



Information concerning the Hubrecht Laboratory and the fifth international 

 team in embryology may be found on page 294. For information concerning the 

 "International Institute of Embryology" and the "International Conference on 

 Organogenesis" (Baltimore, Sept. 1964) please see page 296. 



P. D. NIEUWKOOP 



