6o Calvert and Boodle . — On Laticiferous Tissue 
As regards the laticiferous vessels of Manihot Glaziovh , 
nuclei have been already found in the transverse connections 
by Dr. Scott 1 , but the question of their more general occur- 
rence was left open for further investigation. As the euphor- 
biaceous genera Manihot and Hevea are the only ones 
which are known to contain articidated laticiferous tubes, 
not included in the orders investigated by Schmidt, the 
occurrence of protoplasm and nuclei in the laticiferous vessels 
of Manihot is a point of considerable interest. 
By treating longitudinal sections of the stem of Manihot 
Glaziovii with ether and staining wfith haematoxylin nume- 
rous nuclei in the laticiferous vessels both of the phloem and 
pith were rendered clearly visible. 
All the figures refer to the latter system. Figs. 7 and 8 are 
from a portion of a stem about millimetres thick at a 
distance of 15-20 mm. from the apex. 
Fig. 9 is from an older portion eight mm. in thickness. 
The presence of perfectly normal nuclei at this stage of 
development shows that they persist when the vessels are 
quite mature 2 . This corresponds with Dr. Scott’s observa- 
tions on Chelidoninm , and with those of Schmidt on members 
of the numerous orders investigated by him. The nuclei are 
seen to resemble those of the surrounding cells in size and 
structure. 
Fig. 9 shows a laticiferous tube passing through the nodal 
mass of lignified pith, the cells of which have mostly lost their 
contents. Here also the nuclei in the tube are perfectly 
distinct. 
Alcohol-material being used, the contents of the laticiferous 
vessels were contracted ; they presented a definite outline, 
such as is described by Schmidt, and their peripheral portion 
stained deeply with haematoxylin, from which one may infer 
the presence of a protoplasmic layer. 
1 Quart. Journ. Microscop. Science, 1884. 
2 We also observed that many of the libriform cells of the secondary wood are 
multinucleate. Dr. Scott mentions the occurrence of multinucleate members in the 
sieve tubes. 
