N. H. SWELLENGREBEL 
350 
preparations this is not the case, because of the contraction of the 
protoplasm. The nuclei are not so pycnotic as those of the sporoblasts. 
At first the walls of the spores stick to the surrounding sporoblasts 
(Diagrams XVII and XVIII), afterwards they become free but still 
adhere to each other in larger or smaller clusters, because of the sticky 
condition of the surface of the spore-wall. 
The young spores are distinctly binucleate, the two nuclei touching 
each other (Diagram XVIII, Fig. 2 a, c). In older spores only one 
large nucleus is to be seen (Fig. 2 d), consequently it may be supposed 
that this single nucleus does arise by the fusion of the two nuclei. It is 
impossible to explain in another way how the sporoblasts, all of them 
being binucleate, could produce mononucleate spores. 
Diagram XVIII. (Magnification of Diagram 11.) Fig. 1. A pansporoblast, sporoblasts, 
and spores adhering to each other. The lines connected with the walls of the spores 
and sporoblasts represent portions of the membranes of other sporoblasts which have 
been cut away by the microtome. Fig. 2. a-c. Binucleate spores, Giemsa’s stain. 
d. Mononucleate spore, Giemsa’s stain. Fig. 3. Spores showing volutin granules. 
a. Diffuse dissemination of the volutin. b. Intranuclear volutin. 
Occasionally the spores contain chromatophil granules which are 
not decolorised by sulphuric acid (l®/o) or Gram’s iodine (after staining 
with methylene blue). Consequently these granules consist of volutin, 
a substance also found by Schuberg (1910) in the spores of Pleistophora 
longifilis. The volutin granules are either disseminated throughout the 
spore (Diagram XVIII, Fig. 3 a) or they are to be found in the neigh¬ 
bourhood of the nucleus. 
