Observations on the Structure of the Nuclei 
in Peronospora parasitica, and on their 
behaviour during the formation of the 
Oospore. 
BY 
HAROLD W. T. WAGER, 
Assistant Lecturer and Demonstrator in Biology in the Yorkshire College. 
With Plate VI. 
I T has long been known that in many of the fungi the repro- 
ductive organs, asci, basidia, spores, etc., contain nuclei 
the presence of these bodies in the mycelium has also been 
more orless satisfactorily demonstrated in many cases. Schmitz 1 
states that, by means of haematoxylin, he has been able to 
show that the cells of all fungi, not including the Schizomy- 
cetes, contain one or more nuclei. He bases his assertions 
upon the fact that these bodies become more deeply stained 
than the remainder of the protoplasm. This method of deter- 
mining the presence of nuclei is, however, hardly satisfactory, 
as in some cases the supposed nuclear bodies are so small as 
to be scarcely distinguishable from the ordinary granules in 
the protoplasm ; moreover, it sometimes happens that, owing 
to defective methods of preparation, the protoplasm forms 
roundish, deeply staining coagulations, which may be easily 
mistaken for nuclei. De Bary 2 , in discussing this question* 
1 Sitzgsber. d. Niederrh. Ges. 1879. 
2 Morphology and Biology of the Fungi, &c., English edition, 1887. 
[Annals of Botany, Vol. IV. No. XIII. November 1889.] 
