1898-99. } ON THE CYTOLOGY OF NON-NUCLEATED ORGANISMS. 485 
Wager, from his first observations, claimed that in S. cerevs7@ a spher- 
ical homogeneous nucleus is to be found placed between the cell wall 
and the vacuole, which, after digestion in pepsin-glycerine solution, 
reveals a granular structure. From this he concludes that it consists of 
deeply stainable granules imbedded in a less stainable matrix. The 
granules are probably formed of chromatin. In budding, the nucleus 
divides directly, and this occurs in the narrow passage between the 
mother cell and the bud. When division is to take place, the nucleus 
places itself opposite the opening and proceeds to make its way into the 
bud, until about half of it has passed through, when it divides ‘com- 
pletely, the products constituting nuclei for the mother cell and the bud. 
In the cell about to sporulate the large vacuoles disappear, the proto- 
plasm is beset with small ones, and the homogeneous nucleus is 
centrally placed. In it, granules, however, soon make their appearance; 
which accumulate in the centre, and look like a nucleolus. In division, 
the outline of the nucleus becomes irregular, and the granules arrange 
themseives in the form of a short rod, surrounded by other portions of 
the nucleus, which stain differently, and appear to form a structure 
like a spindle. The granules form two groups, each of which constitutes 
a nucleus, and each of the two nuclei divides in the same way, forining 
thus the nuclei of the spores. Around each of these nuclei protoplasm 
accumulates and a membrane forms. This form of nuclear division 
Wager regards asa simple form of karyokinesis. In S. Ludwzgzz, he 
found a nucleus with membrane, and a nuclear network and nucleolus 
the latter containing all the chromatin. In division, the nucleolus 
increases in size, and divides, each part becoming a nucleus. 
In the paper detailing his later observations, Wager gives a fuller, 
and, in some respects, a considerably different account of the yeast cell. 
In the fresh, actively growing organism the cell contents are clear and 
homogeneous, with sometimes one or more bright refracting granules. In 
this condition a vacuole or vacuoles can be seen, and in each occurs at 
least one refracting particle which is in a state of movement. The 
vacuoles disappear in a later stage of fermentation, and the protoplasm 
then appears homogeneous and clear; but, when the culture medium 
becomes exhausted, the contents become granular and_ possess fat 
globules, the protoplasm shrinks from the cell wall,and the cell presents 
an appearance of disintegration. In compressed yeast, on the other 
hand, the cells are rich in refracting granules, which are sometimes 
uniformly distributed through the protoplasm, sometimes located around 
the vacuoles, or grouped together at one side of the cell. 
In regard to the nuclear apparatus, Wager distinguishes two struc- 
