CLASSIFICATION 401 



the common blue mould (Penicillium glaucum) while killed by boiling- 

 water can withstand dry heat at 120 C. for some time. 



Classification. In considering now some of the pathogenic micro- 

 organisms of a higher development and more complicated morphology 

 than the bacteria, the classification proposed by Lackner-Sandoval 

 and adopted by Petruschky in his contribution on pathogenic tricho- 

 mycetes in Kolle and Wassermann's Manual will be followed. Pet- 

 ruschky divides the hyphomycetes into the trichomycetes (hair fungi) 

 and the higher hyphomycetes. The former are again subdivided 

 into (1) leptothrix, (2) cladothrix, (3) streptothrix, and (4) actino- 

 myces. 



The first two genera are nearly related to the bacteria or schizomy- 

 cetes, while the latter two are clearly members of the order of hypho- 

 mycetes or eumycetet, 



1 . LEPTOTHRIX. These present themselves as stiff, slender filaments 

 which do not show any branching and on which dividing processes 

 can rarely be observed. 



2. CLADOTHRIX. These are filaments with pseudobranching. 

 The branching effect is produced by a protrusion of the protoplasm 

 through the membrane and a rapid breaking up of the filaments into 

 short rods which assu me the character of bacilli. 



3. STREPTOTHRIX. This genus forms a true branching mycelium 

 with septa formation and the production of fruit-bearing filaments. 

 The latter break up into short segments which form chains of exo- 

 spores, or conidia. 



4. ACTINOMYCES. This is really a streptothrix and it systematically 

 does not differ from the latter. It shows, however, the peculiar 

 property when invading tissues as a pathogenic microorganism of 

 forming in the pathologic lesions very characteristic stars, composed 

 of the ends of swollen hyphons or filaments, arranged in rosette form. 

 On this account the organism has received the name of ray fungus, 

 or actinomyces, and it is well to retain it and classify separately the 

 pathogenic streptothr.ces showing this property. 



1. Leptothrices. The?.e are represented by a species frequently 

 found in the mouths of persons and known as Leptothrix buccalis. 

 The organism is, as a rule, a harmless saprophyte, but it has some- 

 times been found as the cause of acute or chronic inflammations of 

 the pharynx in man. Piana has observed a case of pleuritis in a dog 

 caused by an organism similar to or identical with the Leptothrix 

 buccalis. 



2. Cladothrices. Cladothrix asteroides is the name given by 

 Eppinger to an organism found as the cause of pseudotubercuiar 

 lesions in guinea-pigs. It is described as consisting of filaments with 

 pseudobranches. The filaments later break up into segments of 

 cuboidal and bacillary shape. The organism grows rapidly at blood 

 temperature, poorly under anaerobic conditions ; and does not liquefy 

 gelatin. It forms round colonies, which subsequently become con- 



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