446 Sargant . — The Formation of the 
chromosomes, great light will be thrown on the relation of 
the process of fertilization to the phenomena of heredity 1 . 
Dr. Valentin Haecker has lately called the attention of 
botanists to this important subject, and has suggested that 
they should re-examine the critical divisions in the test case 
of Lilium Martagon 2 . A complete account of the formation 
of the sexual nuclei in this plant was given in 1891 by 
M. Guignard in his well-known paper, ‘Nouvelles Ftudes sur 
la Fecondationd The four spermatogenetic and three 
oogenetic divisions which follow the reduction in number of 
the chromosomes are minutely figured and described in this 
memoir. It is shown in each case that the chromosomes are 
divided longitudinally. Dr. Haecker has however pointed 
out that the first karyokinesis on either side is figured as 
differing somewhat from those which succeed it, and he has 
hinted that the cause of this distinction may be that during 
this nuclear division the apparently longitudinal fission of the 
chromosomes is in fact a transverse one. In view of the 
theoretical importance of such a discovery, it seemed worth 
while to make a detailed study of the whole series of nuclear 
divisions from this point of view, paying particular attention 
to the long period of growth and development which precedes 
the appearance of the reduced number of chromosomes on 
either side. I was encouraged to undertake this work by 
Dr. D. H. Scott of Kew, to whose advice and sympathy 
I have owed much throughout its progress. It has been 
entirely carried out in my laboratory at Reigate. 
Before proceeding further it will be necessary to define 
more exactly the limits of the investigation. The genealogy 
of the male and female generative nuclei of any given plant of 
Lilium Martagon extends back through a long line of nuclear 
divisions to the first division of the fertilized ovum from which 
1 For a discussion of Dr. Haecker’s hypothesis and its relation to Professor 
Weismann’s Reduction Theory, see Riickert, Die Chromatinreduktion bei 
der Reifung der Sexualzellen — Ergebn. d. Anat. u. Entw. (Merkel u. Bonnet), 
1894. 
2 Vid. Haecker, 1 . c. pp. 99-101. 
