iqiq] DRECHSLER— ACTINOMYCES 71 



ent region from Lachner-Sandoval, and properly relegating the 

 fragmentation of the latter to the category of degenerative changes. 



Gilbert (5) found some lateral branches to begin the process 

 of forming spores by becoming differentiated into highly refrac- 

 tive and weakly refractive portions. Constrictions later appear, 

 unassociated with visible changes inside the filament, and soon the 

 spores are completely cut off. Gilbert designated the process as 

 segmentation, following Lachner-Sandoval, who, however, had 

 actually observed septa appearing more or less simultaneously with 

 the constrictions, their appearance being followed by the enlarge- 

 ment and rounding up of the segments to form spores. 



MiEHE (17), in his study of Actinomyces thermophilus, only inci- 

 dentally examined the mode of sporulation. He believed spores 

 were produced singly on very short stalks attached laterally to the 

 main hyphae, or possibly by successive contractions in chains. 

 In either case conidia were produced, not by the segmentation of 

 a completed fiJament, but by the development of a structure which 

 at no time constituted a cylindrical, continuous hypha. This 

 account, in general, bears strong resemblances to the later descrip- 

 tion by ScHtJTZE (21) of Actinomyces monosporus, a form in which 

 the spores are borne singly on delicate stalks in racemose arrange- 

 ment on a thicker axial filament. It might well be questioned, 

 however, whether forms like this, which depart so widely from the 

 main morphological trend of Actinomyces, are properly to be 

 assigned to this genus, even if allowance is made for much Hberality 

 in the definition of hyphomycetous form-genera. 



The same criticism, however, cannot be extended to the condi- 

 tion described by Schijtze in his strain of Actinomyces thermophilus. 

 In his account of this species its author strongly defended Neu- 

 kirch's position that the mode of sporulation was one of fragmen- 

 tation. However, while Neukirch found long filaments converted 

 into spore chains by successions of protoplasmic contractions, the 

 long portions finally becoming resolved into ultimate spores, 

 ScHtJTZE found that only short terminal portions or short lateral 

 branches yielding about 5 spores were involved. According to 

 Neukirch, the slightly refractive spaces between the masses of 

 protoplasm that later develop into spores are entirely empty, and 



