142 RIKER: CHONDRIOMES IN CHARA 
(15) as Chara fragilis. A study was also made of Chara verrucosa, 
collected at Oberlin, Ohio. 
METHODS 
A number of killing agents were employed, including Carnoy’s, 
Jeffrey’s, Flemming’s, Merkel’s, Benda’s, and dilutions of a 1 per 
cent chrom-acetic stock solution. The best results were obtained 
with Flemming’s, Benda’s and Merkel’s solutions, all of which 
belong to the group recommended by Guilliermond (8) as causing 
the least change from the living condition. Care must be used 
while fixing the material because the chondriomes are rather 
easily destroyed by strong reagents. Flemming’s weaker solution 
was tried at o° C. and 50° C., but the best results were secured when 
the killing agent was of the same temperature as the water in 
which the Chara grew. Sections were cut at 5 and 7 un, and 
stained with Haidenhain’s iron-alum haematoxylin or Flemming’s 
triple stain. Such stains as Giemsa’s, Leishman’s, and Wright’s 
(Mallory and Wright) were also tried. These possess a certain 
value for this type of work because of the differential qualities 
and the rapidity of the staining, but they are likely to cause arte- 
facts due to the precipitation of the stain. The lack of perma- 
nence of these stains is a further disadvantage. 
Division figures are not easy to secure. Preliminary tests, 
in which growing tips were killed at intervals throughout the 
twenty-four hours, showed that mitotic division was most active 
at ten o’clock at night, and so for the final results the material was 
killed at this hour. | 
RESULTS 
Since it is during the nuclear division that these chondriomes 
have their origin, it is necessary to study all the mitotic stages 
beginning with the resting cell. 
While the cell is in the resting stage, the nucleolus shows 
refractive spots or granules. A similar appearance has been 
reported by Digby (5) and others in a variety of plants. As the 
spireme is formed, the nucleolus becomes irregular in shape, 
while it seems that streams of its contents flow out into the spiral 
thread (Fics. 1 and 2). Mottier (13), while writing about 
nucleolar observations, says it is reasonable to suppose that the 
