220 
Katharine Foot and E. C. Strobell 
nous la confirmons chez le chat: nous voyons ici 36 chromosomes et 
dans la premiere figure polaire 12 (soit 24)». 
Certain variations in the number of chromosomes have been admitted 
even by those who accept the continuity hypothesis, and various ex- 
planations have been offered to justify the assumption tliat these are 
only apparent inconsistencies. For example, premature division or re- 
tarded division of one or more chromosomes at the metaphase or ana- 
phase, or fragmentation or fusing of one or more chromosomes of any 
group. An attempt to count the number of chromosomes would indeed 
be useless if all variations are to be set aside by claiming fragmentation 
of individual chromosomes in those cases where the presence of one 
or more extra chromosomes may embarrass a theory, or by claiming 
fusion of two or more chromosomes when the requisite number is not 
present. 
We would not question the probabüity that Variation in the number 
of chromosomes may be caused in some cases, by fragmentation or fusing 
of individual chromosomes, but that this method is adequate to account 
for all variations is rendered doubtful by those cases in which the number 
of chromosomes may remain typical, while the relative sizes vary, for in 
these cases there is evidently a readjustment of the chromatin which is 
independent of the number of the chromosomes. This is in accord with 
the accumulating evidence which indicates that the chromosomes re- 
present a Segregation of smaller units, a feature rarely questioned for 
other organs of the cell — the nucleolus, the centrosome and the various 
mitochondrial structures. Farmer’s conclusions would seem more in 
accord with many of the facts, “The chromosomes like other organs are 
subject to change botli as to size and number”. . . They are “an expression 
of the organizing function of the cell as a whole”. 
This conception of the chromosomes as organs of the cell is in accord 
with most authors who doubt the fundamental significance which has 
become associated with these structures. Fick (1907) expresses this 
idea very clearly, »Die Annahme, daß es sich bei den Sonderchromosomen 
um ein besonderes Individuum handelt, das sich von Zellgeneration 
erhält, bringt nicht einmal eine wesentliche Erleichterung der Erklärung, 
ihr Auftreten bleibt nach wie vor wunderbar und unerklärt. Das Er- 
scheinen verschieden gestalteter bzw. sich verschieden verhaltender Chro- 
mosomen in den Zellen desselben Individuums gehört eben in diesen 
Fällen zum Typus der Art, es ist das adäquate Produkt der betreffenden 
chemischen und physikalischen Verhältnisse und ist ebenso unerklärt 
wie irgendwelche andere besondere charakteristische Einrichtung bei der 
