1897 | OBSERVATIONS ON THE MYXOBACTERIACE: 401 
except in very favorable instances, the true nature of the process 
is not at once apparent, although, when once ascertained, it has 
been readily demonstrated in all the species examined. By 
removing and crushing guttulae of Myxococcus rubescens, for 
example, which have formed on agar in pure cultures, selecting 
preferably such as have recently begun to rise from the sub- 
Stratum, it is not difficult to obtain in abundance all stages 
illustrating the process of sporulation; and by staining the 
material with Delafield’s haematoxylin, or with eosin, the mature 
spores which resist stains are at once differentiated in the prep- 
aration from the immature conditions. It may be thus defi- 
nitely determined that sporulation consists in the direct trans- 
formation of single rods into single spores. By a gradual 
inflation, involving a corresponding shortening of the rod in the 
direction of its long axis, even the longest individuals eventually 
assume a spherical form, and through the deposition of material 
on the inner surface of their walls are gradually converted into 
thick-walled refractive spores. The successive steps in this 
transformation may be more readily understood by reference to 
IE. 36 (a—j), and it may be mentioned that, as is indicated in 
the figures, a marked enlargement is first apparent at one end of © 
the rod, the progressive transformation gradually involving the 
Whole cell. As in other members of the group, the rods, when 
they run together to sporulate or to produce cysts, become 
thickened and somewhat shortened, and the more densely granu- 
lar portion of their contents tends to collect in somewhat definite 
masses. Even before the rods have begun to show the terminal 
inflation just mentioned, one of these masses towards the : 
extremity of the cell may be seen to be distinctly larger than the 
fest, which tend to disappear as the transformation of the rod 
Progresses; the larger mass becoming more and more distinct 
and clearly defined, taking a deep stain with either eosin or 
matoxylin. As the spore assumes a more rounded form this 
'y staining mass comes to occupy a central position, and has © 
. the appearance of a well defined nucleus-like body (/ and 2), | 
Oat continues to stain pies and a = ae wall 
