82 BOTANICAL GAZETTE [January 



by the appearance of one or several deep staining granules within 

 the spore. Whether the latter represent nuclei or bodies of meta- 

 chromatic material cannot definitely be determined. It seems 

 not at all improbable, however, that some of the structures that 

 can be differentiated within the more mature spores, particularly 

 those characterized by uniform size and moderate staining proper- 

 ties (figs. I, 2, ;^^, :^s) are nuclei. In Actinomyces IV and XII they 

 may frequently be distinguished comparatively early, before the 

 septa, with which they alternate in regular succession, show any 

 perceptible constriction, indicating that their existence is not 

 related to the subsequent disposition of the partitions (fig. 67). 

 When two of these bodies occur in the same spore they uniformly 

 occupy opposite or diagonal positions (fig. 2, a, di). The question 

 arises why these bodies, if they actually represent nuclei and not 

 structures originating de novo, cannot be distinguished in the young 

 continuous sporogenous hyphae. The only explanation that can 

 be advanced is that the protoplasm in the earlier stages is too dense 

 to make possible any conspicuous contact between cytoplasm and 

 nucleus. Later, with the attenuation and vacuolization of the 

 cytoplasm that occur with the maturation of the spore, apparently 

 as the result of the deposition of a special wall, the nucleus becomes 

 increasingly distinct, and in some species it constitutes the only 

 spore structure clearly visible in the stained preparation (fig. 41). 

 It cannot be denied, however, that granules having more the 

 appearance of the metachromatic granules found in degenerate 

 sterile filaments occur in the spores of some species, either alone or 

 together with a nucleus-like body. They differ from the latter 

 in taking a deeper stain; in having an absolutely smooth contour; 

 in offering considerable variability in size; and when present in 

 numbers assuming no definite orientation with reference to each 

 other. They have been noted in those species in which the septa 

 associated with the delimitation of spores is particularly massive; 

 and in Actinomyces II (fig. 8/) their derivation from the excessive 

 wall material seems reasonably well established. After the septa 

 have separated along a median plane, the deep staining substance 

 at each end may contract, yielding a number of spherical bodies 

 inside of the spore. This process is probably of a more or less 



