640 



PATHOGENIC MICROORGANISMS 



Cultivation of Microsporon furfur has been successfully carried 

 out by many observers.' Growth is particularly characteristic upon 

 potato, white or yellowish-white colonies appearing within fovu- or five 

 days and rapidly spreading over the entire surface of the potato. 



Thrush {Soor or Muguet; O'idium albicans). — Thrush is a localized 

 disease of the mouth occurring most frequently in children suffering 



from malnutrition or it occurs, under con- 

 ditions of uncleanliness, upon an area of 

 catarrhal inflammation of the mucous mem- 

 brane. 



The microorganism which causes the 

 condition was first described by Langenbeck 

 in 1839, and has, since then, been studied 

 by many observers. It was successfully 

 cultivated by Grawitz ^ in 1886 and recog- 

 nized by him as belonging to the hypho- 

 mycetes. The most careful cultural studies 

 which have been made upon the Oidium 

 albicans are those of Linossier and Roux.' 



Morphologically, the oidium consists of 

 budding cells, resembling those of yeast, 

 which, under certain conditions, can pro- 

 duce mycelia and hyphae from which 

 spores are developed. Two main varieties 

 are described, that which produces large 

 spores and liquefies gelatin in culture, and 

 that which gives rise to smaller spores and 

 fails to liquefy gelatin. In many cases only 

 the yeast-like budding cells can be found; 

 these, however, when subjected to unfavor- 

 able cultural conditions, may be induced to 

 send out hyphse and form spores. Like 

 yeasts, but to a lesser degree, the Oidium 

 albicans causes fermentation in sugars. It 

 develops best under slightly acid conditions 

 and in the presence of free oxygen, upon gelatin and agar. 



Favus {Ackorion Schoenleinii). — Favus is a disease attacking chiefly 



1 Kotjar, Ref . Baumgarten's Jahresberioht, 1892. 



» Grawitz, Virch. Arch., 1886. 



' Linossier et Bovx, Comptes rend, de I'acad. des sci., 1889. 



Fig. 149. — Penicillium 

 GLAUCUM. A. Showing septate 

 mycelia. B. End of a hypha 

 ■ — ^branching into two conidio- 

 phores, from which are given 

 off the sterigmata. From the 

 ends of these are developed 

 the romid conidia. (After 

 Zopf.) 



