44 



MORPHOLOGY AND CULTURE OF MICROORGANISMS 



rise to a spindle ending in a centrosome at either extremity, while two 

 chromosomes form the equatorial plate at the center (5). Each of 

 the two chromosomes divides and the four resulting chromosomes are 



distributed between the two poles (6-8) where 

 they form the two daughter nuclei (Moreau). 

 METACHROMATIC CORPUSCLES AND RESERVE 

 PRODUCTS.- -The vacuoles always contain a 

 great many shining granules, showing Brownian 

 motion and capable of being stained in the living 



I 



FIG. 28. 



FIG. 29. 



FIG. 28. Dematium species stained by a method permitting the differentiation 

 of the metachromatic corpuscles, i, Filament. 7 and 9, Yeast forms. 9, Yeast 

 form starting to bud from mycelium. The metachromatic corpuscles are situated 

 in the vacuoles in the form of small grains joined in chains (6) or isolated. Many 

 appear like large granules (9). n. Nucleus, v.c. Vacuole with metachromatic 

 corpuscles. 



FIG. 29. Various stages of the development of the ascus in Aleuria cerea. 

 i and 2, Young asci with their nucleus and many metachromatic corpuscles. 3, 

 Fragments of an ascus after the second nuclear division. 4, Ascus, still young, 

 in which the ascospores are surrounded by metachromatic corpuscles. 5, Older 

 ascus in which most of the metachromatic corpuscles have been absorbed by the 

 ascospores. 



state by neutral red and methylene blue. These bodies have staining 

 qualities which permit them to be easily characterized. They are stained 

 a violet-red by most of the basic dyes, aniline blue or violet. They also 

 take on a very pronounced reddish tinge with hematoxylin (Fig. 28). 

 By reason of this property of metachromatism, they have been called 

 metachromatic corpuscles. These bodies, which are very common in the 

 Protista, have been found in yeasts, bacteria, algae and protozoa. The 

 chemical nature of the substance constituting them is still unknown, 



