THE GENUS ASPERGILLUS. 325 



Forms that are otherwise identical with A . niger, but differ in 

 the slower and less abundant formation of conidia, should hardly 

 be classed as separate species ("small species"), as was done by 

 COSTANTIN and LUCET (I.) in the case of Sterigmatocystis pseudo- 

 nigra, this method leading to confusion in many respects. 

 GASPERINI (I.) found on gall-nuts, apple kernels, and solutions 

 of tannic and citric acids, a species, A. violaceofuscus, which 

 produced conidia measuring 3-3.5 by 5-6.5 ^> though recalling 

 A . niger in habitat and other features. 



Aspergillus candidus /., WEHMER (XVII.), occurs preferably 

 on old, decayed vegetables of various kinds (mouldy pumpernickel, 

 rotten cucumbers, rotten grapes on the vine, spoiled cabbage- 

 broth, mouldy cotton-seed meal, and mouldy grain), as well as on 

 putrescent urine, old cheese, &c. The ordinarily sluggish growth 

 of the cultures on the usual substrata also indicates that its food 

 requirements are rather peculiar ; and it seems to prefer an 

 alkaline reaction of the medium. Probably several of the white 

 species described in the literature will have to be amalgamated 

 with this one; but at present it is impossible to say if it is 

 identical with Link's old species. The surface, which is perfectly 

 snow-white, turning creamy in old cultures, and even brown in 

 those on wort gelatin, exhibits two forms of conidiophore : one 

 with spherical globule and branched sterigmata, corresponding 

 exactly with those of A. niger (see 9 in Fig. 163), whilst the other 

 is much simpler and smaller, the sterigmata being unbranched. 

 The conidia are mostly ellipsoidal, smooth or covered with fine 

 dots, and 2.5-4 yu in diameter. The A. albus, described by 

 WILHELM (I.) in 1877, with its spherical globule and branched 

 sterigmata differing from the specimens found nearly always on 

 spoilt barley by P. LINDNER (XXXIII.) probably corresponds to 

 the larger form. A critical investigation of the white species, on 

 the basis of culture experiments, is highly desirable, this group 

 being at present in a chaotic state, unless one is content with 

 imperfect descriptions and artificial specific names (see the forms 

 arranged by WEHMER (XVII.) and LINDAU (I.)). 



Aspergillus nidulans ( /Sterigmatocystis nidulans, Eidam). 

 This species, which is pathogenic when injected into the blood 

 (optimum temperature about 40 C. !), and is also sometimes 

 found in the human ear, was first discovered by EIDAM, in 

 1883, in a humble-bees' nest. It is a scarce, handsome green 

 species, and is rendered interesting by its sclerotia, which, how- 

 ever, has only been observed and studied in a single instance, 

 Eidam having failed to discover it again. In 1904 SAITO (I.) had 

 a specimen, which he did not examine further, but states that the 

 fungus occurs in the air in Japan, associated with A. glaucus. The 

 tough-skinned conidiophores (Fig. 1 76) on the green surface (which 

 afterwards becomes discoloured) measure up to 0.6-0.8 mm., but 

 are frequently only one-third to one-half that size. The branched 



