98 



THE FUNGI IMPERFECTI AND THE ASCOMYCETES 



pathogenicity has not been proved convincingly, together with an 

 excessive splitting of genera and species, and the inclusion of many 

 fungi. under more than one name with no indication that they refer 

 to the same fungus, makes this book of limited value. Interested 

 bacteriologists are referred to the international journal Mycopath- 

 ologia for recent work on medical mycology. Under an international 

 editorial board, published in Italy and printed in the Netherlands, it 

 is a war casualty. It is to be hoped that this journal will be revived. 

 Aspergillus. The word aspergillus (or aspergillum) means a spe- 

 cial type of brush for sprinkling holy water used in the ceremony 



the ''Asperges" which Latin word is 

 the first one of Psalm 51:7 that is 

 sung during the ceremony. The re- 

 semblance of the common Aspergillus 

 niger to this brush is striking. The 

 literature on this important genus is 

 enormous but two recent books have 

 so thoroughly covered the field from 

 so many points of view that further 

 references here are neither necessary 

 nor desirable. These books are Thom 

 and Church's monograph The Asper- 

 gilW^^ and Thom and Raper's A 

 Manual of the Aspergilli}^ 



The genus Aspergillus may be rec- 

 ognized by the very characteristic 

 arrangement of the conidia and conidiophores. The unbranched 

 conidiophore arises from an enlarged cell of the vegetative mycelium, 

 the foot cell, and terminates in a swollen portion, the vesicle. From 

 the latter, there arise a number of little stalks of characteristic bottle 

 shape, the sterigmata or, as they are sometimes called, the phialides. 

 From these primary sterigmata there may arise one, two, or, rarely, 

 more secondary sterigmata. From the tips of the primary sterigmata 

 in some species, or from the tips of secondary sterigmata in those 

 species which have them, chains of conidia are borne. A conidium 

 is formed by a partial abstriction of the sterigma, which has elon- 

 gated lightly, followed by formation of a septum separating the 

 conidium from the sterigma. Further cutting off of the tip of the 

 sterigma thus results in more conidia. Since these spores remain 

 attached together, they occur in chains and the whole arrangement 

 presents the spores arranged on compact masses, "conidial heads," 

 at the tip of the conidiophores. In some species the sterigmata and 



Fig. 45. Aspergillus niger: a, 



vesicle and sterigmata; h, foot 



cells; c, conidia. 



