CULTURAL STUDIES OF SPECIES OF PENICILLIUM. 



INTRODUCTION. 



In a previous paper ' two species of PeniciUium were shown to 

 secrete the proteolytic enzyms which ripen certain varieties of 

 cheese. The effort to identify these organisms necessitated the 

 culture and comparison of numerous other species and a study of 

 the literature of nomenclature for the whole of thegenus Penidllium. 

 The difficulties encountered in deciding whether to discuss these 

 forms under old names or to describe them anew from cultural data 

 led to the extension of this study beyond the forms occurring in a 

 dairy investigation so as to include any obtainable species, and 

 especially all species whose identification under published names 

 could 1 stablished. 



Many recent studies have linked particular chemical and physio- 

 logical activities with the presence of particular species of fungi. 

 When such data relate to known species -identifiable species — our 

 knowledge of the metabolism of these forms has been greatly in- 

 creased. When, as has often happened, the generic name alone is 

 given in a group so diverse in its activities as PeniciUium, such data 

 only add to the confusion. Whether the observations apply to all 

 of the species of the genus or to a single unnamed species is left un- 

 settled. To give real utility to such work, some one must test the 

 applicability of the data to each species under consideration. On 

 account of their ease of cultivation and the notion that there was a 

 single common green species legitimately named P. glaucum, species 

 of PeniciUium have formed the subjects of many such investigations. 

 In very few of these cases are sufficient data regarding morphology 

 given to w arrant even a guess as to t he species used. An e.xaiuinat ion 

 of the present stat us of specific uomenclat lire in t he genus will t here- 

 fore furnish a sounder basis for further studies of their activities. 



This paper represents cultural work which has continued more 

 than four years and includes those species lor which the dat a obt ained 

 seem abundantly t<> justify the characterization offered. Some of 

 these forms have been cultivated for the whole period, others for a 

 less time. \o claim to monographic completeness can be made. In 



"The figures refer to the list of literature at end of bulletin. 



