336 MORPHOLOGY OF THE ASPERGILLACE^. 



since the shape and size of the ripe conidia have hitherto been 

 found very constant, and there is no really accurate experience of 

 any variability in the morphological characteristics of one of these 

 forms, if we except the irregular branching of the conidiophores. 

 Reports on sclerotia are given by WINTER (IV.) and GUE- 

 GUEN (II.), and on the formation of coremia by BREFELD (II.) 

 and HENNINGS (II.). 



The two following species can be differentiated from 

 Bref eld's fungus on the ground of THOM'S investigations (II.), 

 and also differ from each other in form and culture. Thorn 

 named them ''Roquefort mould" and "Camembert mould" 

 respectively ; but, in the absence of any specific names, they may 

 be provisionally termed P. Roquefort and P. Camembert. 



Penicillium Roquefort, THOM'S (II.) Roquefort mould, hitherto 

 generally called P. glaucum, Link, differs clearly from Brefeld's 

 P. glaucum by the size of its conidia, which are about twice as 

 large as those of the latter. The position of this species, which 

 is of regular occurrence, in the conidiophore-bearing stage, in the 

 green veins of ripening Roquefort cheese, is left an open question 

 by Thorn. The conidiophore is 200-300 JJL high and 4 p thick, 

 the average height of the conidia heads is 90-120 ju ; and the 

 branchings are arranged in irregular whorls, carrying sterigmata 

 9-11 jji long and 2.5 JJL across. The conidia are bluish green, 

 mostly spherical, smooth and large, being 45 yn in diameter. 

 The colour of the vegetation is dark green, afterwards turning to 

 a dirty brown, the underside being yellowish white. No asco- 

 spores have been detected. Only a slight liquefactive action was 

 exerted on sugar gelatin ; and red litmus was rapidly turned blue. 

 The germination of the conidia and development proceed rapidly, 

 an abundant mycelium, with conidia, being frequently produced 

 within thirty-six hours. This rapid growth distinguishes the 

 species from P. Camembert, and the conidia are less sensitive to 

 drought, sometimes retaining their germinating power for months. 

 According to CONN, THOM, BOSWORTH, STOCKING and ISSAJEFF (I.), 

 a bitter taste is imparted to the cheese. Thorn states that the 

 species is characteristic for Roquefort cheese, though it occurs 

 on many other substrata and appears to be distributed every- 

 where. 



Penicillium Camembert, the Camembert mould of THOM (II.), 

 is a distinct species which plays a constant part in the ripening of 

 Camembert cheese. CONN, THOM, BOSWORTH, STOCKING and 

 ISSAJEFF (I.) call it simply Camembert fungus, leaving the 

 species undefined owing to lack of sufficient description. 

 THOM (II.) has also recently described it more closely under 

 the name Camembert mould (P. album, Epstein ?), and it is 

 probably identical with ROGER'S (I.) P. candidum from Brie 

 cheese (1898), and EPSTEIN'S (I.) P. album from Camembert 

 cheeso (1902), which have not been morphologically described. 



