Chromosomes in the Sexual Cells. 
97 
is accomplished in the same manner as it seems to him to 
take place in Phanerogams. The reduction in animals takes 
place, as he thinks, in the mother-cells, and the chromosomes 
therefore already appear in the reduced number at the be- 
ginning of the two maturation-divisions. Each of the chromo- 
somes undergoes double longitudinal splitting, by which they 
are prepared at the same time for both divisions. He believes, 
however, that there exists a complete homology between 
the botanical and zoological observations. Strasburger even 
asserts decidedly that reduction-divisions ( Reduktionstheil - 
ungen) in Weismann’s sense do not exist, either in plants or 
anywhere 1 , that is to say, such divisions in which the re- 
partition of the chromosomes takes place without a preceding 
longitudinal splitting. 
The question is, if the matter can be settled in this way or 
not. With regard to the literature relating to this subject, 
Strasburger refers us to his work, ‘ Schwarmsporen, Gameten, 
pflanzliche Spermatozoiden und das Wesen der Befruchtung.’ 
This work was published in 1892. During the last years, 
however, a series of papers 2 have been published which 
promise a solution of the problem of reduction in a perfectly 
contrary direction. 
In these papers it is partly indirectly concluded from com- 
parison with other processes of division, partly proved by 
direct observation, that the two maturation-divisions are not 
introduced by a double longitudinal splitting, but only by 
1 Compare Uber periodische Reduktion u. s.w., Biol. Centralbl., xiv. p. 851. 
In the English translation, Annals of Botany, viii. p. 310, Strasburger more 
cautiously says, ‘ Such divisions do not take place among plants.’ 
2 (1) O. vom Rath, Zur Kenntniss der Spermatogenese von Gryllotalpa vulgaris , 
Latr. Arch. f. mikr. An., V. 40, 1892 ; (2) V. Haecker, Die heterotypische Kern- 
theilung im Cyklus der generativen Zellen, Ber. Naturf. Ges. Freib., V. 6, 1892 ; 
(3) V. Haecker, Das Keimblaschen, seine Elemente und Lageveranderungen I, 
Arch. f. mikr. An., V. 41, 1893 ; (4) O. vom Rath, Beitrage zur Kenntniss der 
Spermatogenese von Salamandra maculosa , Zeitschr. f. wiss. Zool., V. 57, 1893 ; 
(5) V. Haecker, Uber generative und embryonale Mitosen, Arch. f. mikr. An., V. 
43, 1894 ; (6) J. Riickert, Zur Eireifung bei Copepoden, Anat. Hefte, V. 4, 1894; 
(7) J. Riickert, Die Chromatinreduktion bei der Reifung der Sexualzellen, 
Ergebn. d. An. und Entvv. (Merkel u. Bonnet), V. 3, 1894. 
