1919] DRECHSLER— ACTINOMYCES 69 



observations led him to believe that the structures represented 

 nuclei. Schutze (21), who applied Neukirch's method of stain- 

 ing, designated the bodies as metachromatic granules. After an 

 examination of their occurrence in the aerial mycelium of a con- 

 siderable number of species, such an interpretation seems, in the 

 opinion of the writer, to offer the greater degree of plausibility. 



The metachromatic material is easily distinguished by a power- 

 ful affinity for most of the stains ordinarily employed in laboratories. 

 In material fixed in alcohol, and treated with Delafield's hematoxy- 

 lin, it retains a nearly opaque stain after all other structures have 

 been completely decolorized. Indications of its presence in the 

 tips of growing filaments, or in sporogenous branches, in general 

 are very infrequent. Some distance toward the origin of the 

 hyphae, associated with a more attenuated or vacuolated proto- 

 plasm, the material makes its appearance in the form of rather 

 minute granules widely separated from one another. As the fila- 

 ment is followed still farther back, the granules increase in size and 

 frequency; often their arrangement is one of much regularity, the 

 individual spherical bodies being of nearly equal size, exactly 

 filling the lumen of the filament, and separated by nearly equal 

 spaces (fig. 42). In other cases the granules seem to coalesce and 

 occupy entire segments of hyphae (fig. 32); and in a few species 

 extensive portions of mycelium were frequently found entirely 

 filled with long unbroken masses of metachromatic substance. It is 

 this property of coalescence of smaller granules, to form incompar- 

 ably larger masses, bearing out the similarity in appearance to a 

 homogeneous liquid with a relatively high surface tension, that 

 makes it diflicult to believe that we are dealing here with anything 

 relating to spores or to nuclei. 



The function of the metachromatic material in the Actinomyces 

 thallus cannot be ascertained with certainty. A number of views 

 have been advanced regarding the role of metachromatic substance 

 in the cell, none of which has gained universal acceptance. The 

 best explanation, in the opinion of the writer, seems to be that it 

 represents an occluded waste product. While its presence in small 

 or moderate quantities in the sterile hyphae bearing the sporoge- 

 nous branchlets is probably more or less normal, its abundant 



