1919] DRECHSLER— ACTINOMYCES 83 



pathological nature, since in the usual type of development the 

 wall material is gradually distributed through the inclosed proto- 

 plasm, causing the normal mature spore, except for the presence of 

 a vacuole, to take an almost homogeneous stain. 



Another indication of the similarity in nature existing between 

 metachromatic material and the deep staining transverse septa of 

 Actinomyces is found in the occurrence of both within peculiar 

 large spherical structures. These structures appear generally to 

 occupy nearly the entire lumen of the filament, and not infrequently 

 are related to local enlargements. Occasionally, however, their 

 diameter is considerably smaller than that of the hyphae (fig. 103). 

 In any case they may contain either one or several peripherally 

 located metachromatic granules, or a uniformly thick, well defined, 

 deep staining, transverse septum, exactly median in position. It 

 is interesting to note that whenever granules occur their surfaces 

 in contact with the periphery of the structure represent portions of 

 convex spherical surfaces conforming accurately to the confining 

 surface; and whenever a septum is found traversing one of these 

 structures considerably smaller in diameter than the filament, it 

 does not extend into the protoplasm, but remains in its finished 

 state as a curious partial partition. 



The germination of the spores of Actinomyces takes place readily 

 in dilute nutrient solutions, such as i per cent glucose solution, or 

 nearly any vegetable decoction. During the first few hours of 

 incubation at a moderate temperature they increase considerably 

 in volume by swelling. From i to 4 germ tubes are then produced, 

 apparently more or less successfully, the approximate number being, 

 in a measure, characteristic of the species. Specific characteristics 

 are expressed also in the diameter of the h^-phae, and in the fre- 

 quency of branching. 



Cryptogamic Laboratories 

 Harvard University 

 Cambridge, Mass. 



