1921] CURRENT LITERATURE 49 
to affect wall material, as, for example, Delafield’s haemotoxylin applied for 
several hours, was not tried. The process of sporulation is held to be similar 
to the division of bacteria, and is generally referred to as a breaking up (“‘Zer- 
fall”’) of the filaments, both aerial and submerged. It appears difficult to 
understand why the irregular degenerative structures developed in submerged 
material, shown in fig. 49, should be designated as spores at all. In fig. 44, 
showing the development of aerial spores, sporulation is represented as involv- 
ing the filament below the point of insertion of a branch, a condition which 
perhaps it might be not at all easy to find realized in any preparation. A new 
type of spore is also described, the “‘ Vierhyphenspore.” The development of 
the latter is initiated by the serena of two short branches at right angles 
near the tip of a filament. The four elements about the intercalary porti 
similarity to the so-called zygospores of certain microorganisms. In spite 
of the remarks of the author, the figures illustrating these structures do not 
impress the reader as anything especially distinctive, and he is left to wonder 
why the author saw here a character recalling the fungi, when he failed 
to find fungus characteristics in the incomparably more distinctive sporogen- 
ous apparatus. 
In general the author seems inclined to minimize the significance of such 
fungus-like characteristics as are revealed even on smear preparations stained 
according to Gram. He recognizes in the Actinomycetes a group of organisms 
occupying an independent position between the fungi and the bacteria, but 
more closely related to bacteria, particularly to those of the acid-fast type. 
As to a taxonomy of species, he offers little in the way of encouragement to 
followers of precedent. The concept of species he holds to be utterly impos- 
sible to apply here, all strains showing an exceptional degree of variability 
under different conditions, and the presence of intergrading strains bridgin 
over whatever differences may be observed between extremes. Moreover, 
rob any attempt at classification of any except a slight historical interest. 
Even the recognition of group species, certainly not a very happy conception 
at best, is held to be futile for the same reasons. One might desire the author 
to have extended his observations on the tendency toward mutation, to include 
besides characteristics like color of thallus, spore color, or abundance of sporu- 
behave in a consistent way, possible significant changes in structure. As the 
direction of relation of the spiral sporogenous hyphae, for example, has been . 
reported to be an invariable specific characteristic, it would have been inter- 
esting to learn whether or not this too is subject to change by mutation. 
