88 A MANUAL OF THE PENICILLIA 



tion formerly maintained by Thom, Thorn and Church, and Thom and 

 Raper, was moved to the Northern Regional Research Laboratory where 

 it formed the nucleus of the Collection developed here. Since that time 

 many additional cultui'cs have been added through isolations made at this 

 Laboratory and through the receipt of cultures from collaborators through- 

 out the United States and abroad. An unusually large number of strains 

 was contributed by Professors W. H. Weston, G. W. Martin, and W. G. 

 Hutchinson, and W. Lawrence White in connection with the study of de- 

 tcrioration of military equipment during World War II. 



Other valuable and noteworthy collections of Penicillia are maintained 

 at the Centraalbureau voor Schimmelcultures, Baarn, Holland by Pro- 

 fessor Westerdijk and her staff, and at the London School of Hygiene and 

 Tropical Medicine by Mr. George Smith in connection with the biochemi- 

 cal studies of Professor Harold Raistrick and co-workers. Over a period of 

 many years we have enjoyed the full cooperation of Professor Westerdijk's 

 laboratory. All of Zaleski's types were sent to Thom in 1928. For the 

 present study a total of almost 300 cultures of Penicillium and related 

 forms were supplied and have been included in our comparative studies. 

 A free exchange of cultures has likewise been maintained between our 

 Collection and that of Professor Raistrick and George Smith. 



We have attempted to include in the present study the most extensive 

 and representative group of Penicillia that it was possible to assemble. 



Cultures discussed in this Manual are maintained as agar slant cultures 

 in our Collection, and have been preserved in lyophil form. It is hoped 

 that this method of preservation, in particular, will keep available for 

 other investigators cultural material truly representative of our species 

 concepts. Selected strains representative of the species recognized in this 

 Manual have been deposited with the American Type Culture Collection, 

 Washington, D. C.; the Centraalbureau at Baarn; and the London School 

 of Hygiene and Tropical Medicine. 



