more its sole activity. This time the war even directly affected this last refuge 

 of the I. I.E. through the German occupation of the Netherlands. Fortunately 

 the building and collection escaped destruction. After the liberation in 1945. 

 Dr. de Lange, no longer in good health, was unable to restore the activi- 

 ties of the Hubrecht Laboratory, so that the last spark of the spirit of the I.I.E 

 seemed to die out forever. 



It was again the Dutch members of the I.I.E. , this time J. Boeke, M. W. 

 Woerdeman and Chr. P. Raven, who took the initiative in 1947 for a second 

 revival of the I.I.E. They were stimulated by the suggestion of Prof. 

 J. Needham, secretary of the International Union of Biological Sciences, 

 to transform the I.I.E. into the "Embryological Section" of the I.U.B.S. Con- 

 sequently, at the general Assembly of the I.I.E. on April 2, 1947, in Utrecht, 

 it was decided to subject the statutes and by-laws of the I.I.E. to a second 

 revision in order to adapt them to this new status. In the following year a large 

 number of new members were nominated in order to fill up the places fallen 

 vacant in the ten previous years. The new statutes and by-laws were adopted 

 at the General Assembly held in Bern in 1949. 



Simultaneously new life was put into the Hubrecht Laboratory by the 

 development of new plans and by the introduction of experimental embryology 

 by the newly appointed adjunct director, Dr. P. D. Nieuwkoop. These 

 plans were realised in the following years, under the general directorship of 

 Prof. Chr. P. Raven. 



A number of aims of the I.I.E. were realised by the Hubrecht Laboratory 

 in the following projects: 1) the reorganisation of the central collection of 

 microscopical slides and alcohol-preserved material; 2) the foundation of a 

 central reprint library on developmental biology with a bibliographical ser- 

 vice; 3) the editing of the "General Embryological Information Service", a 

 periodical aimed at stimulating international co-operation; 4) the editing of 

 developmental Normal Tables, in casu one of an anuran species, elaborated 

 by an international team of specialists; 5) the establishment of a number of 

 adequately equipped working tables for individual guest-workers as well as 

 for international teams of young scientists. 



These international activities called for a close co-operation between the 

 I.I.E. and the Hubrecht Laboratory. On the other hand, the character of the 

 I.I.E., as the Embryological Section of the I.U.B.S., required an independent 

 development of this institution into a representative, world-wide organisation 

 of embryologists. After a period of trial and error a satisfactory form of coope- 

 ration between the two institutions seems to have been found, which guaran- 

 tees the independence of both. This co-operation has taken the form of, on the 

 one hand, an advisory function of the I.I.E. in those international administra- 

 tive and scientific activities of the Hubrecht Laboratory which are sponsored 

 bv the I.I.E.. and, on the other hand, an advisory membership in the Board 

 of the I.I.E. for the Director of the Hubrecht Laboratorv. who acts as adjunct 

 secretary-treasurer, since the administration of the I.I.E. is carried out at the 

 Hubrecht Laboratory. 



The very rapid growth of the science of embryology, and the development 

 of several specialisations within this field called for a further extension of 

 the number of active members, which was first raised to 60, and later to 75. 



The restricted membership as such, however, was not in agreement with 

 the general character of the sections of the I.U.B.S., which had an open mem- 



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