542 Lewis. — -The Behaviour of the Chromosomes 
re-formation as maintained by Farmer (’07), Mottier (’03), Foot and Strobell 
(’07) and others, then it becomes at once evident that the segments are 
formed anew and that the material primordia, pangens, or chromosomes 
are again shuffled and grouped into new combinations. Such a view leaves 
meaningless the longitudinal fission of the spirem during the prophase of the 
first mitosis, as well as that of the chromosomes during the anaphase. 
These two fissions have generally been regarded as one and the same, and 
as being concerned with an equational division which is completed during 
the homotype mitosis. But this supposition demands the morphological 
continuity of chromosomes, an hypothesis concerning which the gravest 
doubts have been raised by the most competent investigators. The homo- 
type division is not therefore, according to this view, analogous to a somatic 
division, the equational part of which took place during the preceding 
mitosis, but is in fact what it appears to be — also a qualitative division. 
The first division is qualitative and reductional. 
General Considerations. 
A more uniform interpretation prevails among botanists to-day con- 
cerning the phenomena of fertilization and reduction than at any time in the 
history of these most perplexing of all questions. That fecundation effects 
an approximate doubling of the number of chromosomes, half of which are 
furnished by each of the fusing gamete -nuclei, has long been known. 
Equally clear has been the knowledge that this number must be reduced at 
some time previous to the formation of the next succeeding generation of 
germ-cells. The method by which this reduction takes place has been a 
very difficult problem, and, although no solution has yet been offered which 
satisfies all of the phenomena observed by different investigators, there is a 
growing tendency toward a common view of the essential nature of the 
process as a whole. 
At present the view which was formerly held by many of the best 
investigators, that the reduction is accomplished in the resting nucleus, and 
after two longitudinal fissions of the spirem the chromosomes are distributed 
essentially in the same way as in somatic divisions, has been almost, if not quite 
abandoned. This view not only failed to harmonize with the observed facts 
of the behaviour of the chromatin, but also failed to furnish a suitable basis 
for theoretical considerations based on the known facts of heredity. It has, 
accordingly, been gradually superseded by a growing belief, which is now 
almost universal, that a true reducing division takes place as proposed by 
Weismann several years ago, although it is quite generally agreed that 
the reduction occurs in the first rather than the second mitosis. This 
change of conception was brought about largely by a more careful study of 
the early prophase of the first mitosis, as well as by a more general accept- 
