Latex and its Functions. 
21 I 
system, and put forward the view that laticiferous tissue has 
been evolved independently along two distinct lines in the 
Euphorbiaceae. 
The elaborate work of Chauveaud 1 in 1891 further com¬ 
plicated the story of the origin of the laticiferous apparatus 
in the order. He finds in such genera as Aleurites and 
Jatropha , an embryonic inarticulate system replaced by an 
articulate one, and was driven to the conclusion that in this 
group the inarticulate system is the more primitive. 
There is still room for a considerable amount of anatomical 
work on the laticiferous elements of the Euphorbiaceae, in 
order that the origin and development of the two systems 
may be traced. 
It seems to me possible that an articulate system may give 
place to an inarticulate one by the gradual substitution of 
elongation and branching of the laticiferous cells for previous 
fusion of them. On the other hand, it might be simpler to 
regard the two systems as of independent origin from simple 
laticiferous cells, if it were not that the results of the work 
of Chauveaud quoted, hardly allow of this. 
The origin of laticiferous tubes from secretory sacs con¬ 
taining tannin, resin, &c., is strongly suggested by such 
groups as the Papaveraceae and Aroideae, where there is a 
gradual transition from secretory cells to true vessels. Again, 
laticiferous plants as a whole are devoid of other secretory 
reservoirs. 
Assuming that secretion, or the holding of substances of 
no further nutritive value, is the primary function of latici¬ 
ferous cells, why is it that in certain groups of plants these 
cells, either by great elongation and repeated branching, or 
by the formation of vessels, have been changed into a com¬ 
plicated system of communicating tubes ? Surely to perform 
some additional function or functions. 
A conducting function is the one which naturally suggests 
itself. Since extracted latex contains such valuable food¬ 
stuffs as proteids and carbohydrates, the view of the tubes 
1 Chauveaud, Thesis. Paris, 1891. 
Q 
