MOLDS 43 



portion. This is the extent of an amitotic or direct division (Fig. 24, 

 2 and s). 



Karyokinesis is usually seen only in the organs of fructification 

 (asci, basidia, etc.) ; nevertheless, in the mycelium of the Sasidiomycetes 

 and Mucorinece, true m6tamitoses have been found. In the Mucorinem 

 for example (Fig. 26), the nucleus loses its membrane (1-4) and gives 

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

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



Fig. 26. — Nucleus of the Mucor (1-4), and various stages of its division (5-8). 



{After Moreau.) 



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 state by 

 neutral red and methylene blue. These bodies have staining quaUties 

 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. 27). 

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

 metachromatic cor pushes. 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, 

 but the name metackromatin is often used for it.* Some authors, among 



^Because of the priority and more exact signification, the names metachromatic corpuscles 

 and metackromatin are preferable to the terms trains 0/ mlutin and volutin given by Arthur 

 Meyer. • 



