INTRODUCTION 



General set-up 



From several sides we received the suggestion that the General Embryo- 

 logical Information Service should not be published annually because of the 

 fact that only a part — about one third — of the subjects changes in the course 

 of each year. One must, however, reahze that the new subjects reflect the 

 actual progress in this field of science and that they are of particular interest 

 for international cooperation. A biennial appearance has moreover the 

 disadvantage that addresses may gradually get out of date. For these reasons 

 we insisted up till now on pubhshing the G.E.I.S. annually. When, however, 

 the majority of contributors and subscribers has the feehng that a biennial 

 appearance of the G.E.I.S. will actually fulfil their desires and does not 

 markedly interfere with the usefulness of the G.E.I.S., we are wilHng to 

 meet this general demand. 



Since not only a survey of the current investigations but also other inter- 

 national activities of the Hubrecht Laboratory find expression in the G.E.I.S., 

 activities which would actually be affected adversely by a biennial appearance, 

 we have the intention to publish a supplement to the preceding issue 

 in the interjacent years. This supplement will contain the general announce- 

 ments of the "Institut International d'Embryologie" and the Hubrecht Labo- 

 ratory, the "Supply and Demand" Service for laboratory animals and the 

 reviews of new textbooks in the field of embryology and in related fields. 

 Thus we hope that these international activities of the Hubrecht Laboratory 

 will develop normally. We have the pleasure to announce you that we hope 

 to be able to offer this supplement free of charge to all the 

 regular subscribers, the subscription fees for the G.E.I.S. being 

 paid biennially with the appearance of each new issue. 



Consequently we intend to pubHsh the sixth issue not until 1955. We 

 should, however, appreciate it very much to have your personal opinion about 

 the question of an annual or biennial appearance of the G.E.I.S. We, there- 

 fore, request you to fill in the attached slip for inquiry and send it us at 

 your earliest convenience, so that we might still be able to publish the next 

 issue in 1954, in case the majority of contributors and subscribers should 

 express themselves in favour of an annual publication. We thank you in 

 advance for your personal cooperation. 



Will you, please, keep us informed about changes in addresses 

 and academic positions, so that no loss of addresses will occur 

 in the rather long period between the appearance of two successive issues 

 of the G.E.I.S. 



The sending 'in o[ data 



We ask your attention for the following points: 



1 . We urgently request you to return forms before August 

 1st. Data received after November 1st cannot be included in 

 the current issue. 



