500 Hai' per. — Cell- Division in Sporangia and Asci. 
cell (Figs. 30-21). The equatorial plane between the groups 
becomes more hyaline, and constriction of the plasma-mem- 
brane gradually cuts the cell in two (Fig. 22). The primary 
cleavage is complete about four o’clock, and the period of 
embryonic growth and division lasts until about seven a.m. 
The binucleated spores are at first naked masses of proto- 
plasm, but soon are covered by a wall. Their protoplasm 
passes into a resting vacuolar condition, and reserve food 
products appear as drops of oil. Frequently a large oil drop 
occupies the centre of the cell, and the nuclei lie at its ends. 
The spores in this ripened condition are difficult to stain, their 
walls being extremely resistent to fixing and staining reagents. 
The best figures were obtained by killing in Flemming’s 
solution, and staining with methylene blue. By this method 
very sharply defined nuclear figures are brought out in 
different shades of blue. The nuclear sap is colourless, 
the nucleolus deep blue, and the chromatin lighter blue. The 
spores are killed, fixed to the slide with albumen-fixative, and 
exposed about five minutes to one-tenth of one per cent, 
methylene blue solution. Spores that have been imbedded 
and sectioned on the microtome are not as favourable for the 
above staining as those freshly killed and fixed without 
dehydration and imbedding in paraffine. After staining, the 
preparations are dehydrated, cleared in clove-oil, and enclosed 
in balsam. The ripe spores lie imbedded in a shining mass of 
intersporal substance which can be stained readily with gentian 
violet. It is similar in all respects to the material in the so- 
called collar, and is presumably an excretion of the proto- 
plasm during the ripening of the spores. As was noted above, 
the method of spore-formation as it occurs here, by cleavage 
of the entire protoplasmic mass from the surface inward, pre- 
cludes the possibility of any comparison between this inter- 
sporal substance and the epiplasm of the ascus. 
Before passing to the germination of the spores we may 
note the second enlargement of the sporangiophore, just 
below the sporangium, which is to become the explosive 
vesicle for firing off the ripened sporangium. It appears first 
