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Botany. — Prof. J. W. Morr presents the thesis for the doctorate 
of Mr. B. Sypxens: “On the nuclear division of Fritillaria 
imperialis 1 and gives a summary of the results. 
(Communicated in the meeting of October 29, 1904.) 
The subject of this investigation is especially the nuclear division 
in the embryo-sac of /y7ti//aria, formerly a favourite material for inves- 
tigations on the subject of nuclear division. 
Mr. Sypkens studied the free nuclear divisions in the parietal layer 
of protoplasm as well as the nuclear divisions in the first layer of 
endosperm-cells which are directly followed by tangential cellular 
divisions. Besides some observations were made on the nuclei in the 
ovules of Tulipa and in the growing-point of the root of Vicia 
Faba. 
All the material was fixed by means of the strong chromo-aceto- 
osmie acid of FreMMiNG. It was for the greater part imbedded in 
paraffin in various ways and was examined in series of sections 
of 2 to 4 wu thickness, stained with gentian violet. Some observations 
were also made by means of the method introduced by var WISSELINGH, 
in which the nuclei are dissolved in chromic acid of about 50°/,. These 
two methods supplement each other; the chromic acid method is to 
be preferred for observations about the chromatic parts, sections 
give more information about the nuclear spindle. But in this investi- 
gation the excellence of both methods was again proved as compared 
with the observation of the nucleus as a whole, which in many 
cases renders it impossible to form an accurate idea about its 
internal structure. 
I will briefly mention the chief results obtained by Mr. SYPKENs 
for the various stages of nuclear division. 
The resting nucleus was studied by means of sections and of 
chromic acid and the results so obtained were in the main a complete 
confirmation of the results published by van WIsseLINGH and by 
GreGorrE and his co-workers Wyeanrts and Brerens. The framework 
of the resting nucleus consists of numerous larger and smaller lamps 
of chromatin, connected by fine threads so that an anastomosing 
network is formed. There is no reason for assuming in this network 
the existence of two constituents, chromatin and linin; the chromic 
acid method as well as coloured nuclear sections show the contrary, 
if only partial washing out of the stain is prevented, as Mr. SypKENS 
did. Those who wish to maintain the assertion about the existence 
of linin-connections will have to bring forth new and valid proofs, 
