FOREWORD 



Animal and plant viruses are of great practical importance be- 

 cause they are disease producing agents. As such they are of interest 

 to pathologists, and research in this direction is heavily sponsored by 

 medicine and by animal and plant industry. This research aims di- 

 rectly at the control of specific virus diseases, but notwithstanding the 

 expenditure of great effort practical success has been very limited. It 

 is true that we have learned something about the natural history of a 

 number of the disease producing agents and that some of them have 

 been isolated and partially characterized but this is not enough to sug- 

 gest remedies. What is needed is an understanding of the behaviour 

 of viruses within their hosts. How do the viruses invade host cells, 

 how do they multiply, how do they interrupt and modify the normal 

 functions of the host cell? These are the problems of virus research 

 which tie this research into the great stream of modern biology aiming 

 at the analysis of cellular functional organization. 



The conference which gave rise to the proceedings here presented 

 arose from the desire to bring the men who work on the three great 

 groups of viruses, those which attack animals, plants, and bacteria, 

 respectively, into one room and to discuss whether and to what extent 

 our respective charges can be brought under one hat. We felt that such 

 a move could be profitable only if each of us did some considerable 

 home work of a double nature, namely, that of preparing an intelhgible 

 statement concerning his own specialty and that of studying the pre- 

 pared statements of the others. To set a background to the general ap- 

 proach an essay by Luria, which had just been submitted for pubhca- 

 tion in Science,^ was circulated among the prospective participants. 

 The preliminary statements were also circulated, and were studied and 

 discussed at home and en route by smaller groups out here and by 

 those who had arranged to make the long trip West together. The 

 conference was in fact proceeding for quite some time before it met 

 as a whole, and it continued for some of us for three days after the 

 meeting around camp fires in Death Valley. When it met as a whole 

 a great deal of formality could be dispensed with. The authors of the 

 preliminary statements confined themselves to briefly recalling the 

 highlights of their papers and then laid themselves open to questions 

 from the floor, of which there were many. Most of these questions 

 were of such a nature as to suggest emendations, additions, or deletions. 

 Rather than print these discussions it was left to each author to in- 

 corporate into his paper whatever profit he had derived from them. 



'Grateful acknowledgement to the Editor of Science is hereby made for permis- 

 sion to reprint this essay. It has since appeared in shghtly modified form in the 

 May 12 issue of Science {HI, 507, 1950). 



