McAllister—Cytology and Embryology. 
599 
ON THE CYTOLOGY .AND EMBRYOLOGY OF 
SMILACINA RACEMOSA, 
BY FREDERICK MC AEEISTER 
The conception of the constancy of the chromosome number 
in the nuclei of individuals of different species and the numeri¬ 
cal equality of the paternal and maternal chromosomes in dip¬ 
loid nuclei as established by Flemming (28), Strasburger (92), 
Gfuignard (33, 34), Van Bene den (4), Boveri (12, 13) and 
their contemporaries, underlies all recent studies of reduction 
phenomena in plants and animals. That this constancy of the 
chromosome number is also the starting point for all studies of 
the individuality of the chromosome is self evident. As has 
been pointed out by Harper (39), the constant recurrence of a 
characteristic number of chromosomes in the nuclei of the or¬ 
ganism during mitosis is nevertheless alone insufficient to estab¬ 
lish the individuality of the chromosomes. Babbs idea (78) 
of the reorganization of the chromosomes from the resting retic¬ 
ulum, involved the material as well as the numerical persist¬ 
ence of the chromosomes. 
Boverbs earlier work on Ascaris (10, 11, 13) demonstrated 
that the same number of chromosomes reappears in the pro- 
phases as had disappeared in the reticulum in the preceding 
telophase, and further that they reappeared in the same position 
in which they had disappeared. 
The discovery by Henking (40) of a permanent difference 
in the form and size of certain chromosomes in the nuclei of va¬ 
rious species, indicating thus a qualitative difference among 
chromosomes, has given considerable further support to the doc¬ 
trine of the permanence of the chromosomes. The accessory 
