Internal Phloem in Gelsemium sempervirens, Ait. 43 
ment of the University of Pennsylvania for 1884, J. G. Shoe- 
maker has a few notes on the stem of Gelsemtum. He remarks 
the widening of the medullary rays, and “the tendency of the 
pith to be penetrated by several plates of large thin-walled 
cells, which divide the pith more or less perfectly into four 
portions.” 
Professor Rothrock, in February, 1885, made a short verbal 
communication to the Philadelphia Academy of Natural 
Sciences concerning this stem. His attention was attracted by 
the fact that the diameter of the pith is greater in a very young 
twig than in a stem four times its size. He notes the presence 
of the four medullary phloem patches, and their encroachment 
upon the pith area. 
A great deal of work has been done upon Gelsemium from 
a chemical and pharmaceutical standpoint, but its structure 
and development have not been thoroughly worked out. The 
root contains an alkaloid gelsemin, which is very poisonous, 
but is a valuable medicine when taken in proper quantities. The 
medicinal properties of Ge/semium were accidentally discovered 
about the middle of this century. An interesting account of 
the discovery and the primitive method of extracting the poi- 
sonous principle from the root is given by William Proctor, Jr., 
in the ‘‘ American Journal of Pharmacy”’ for 1852. 
Other records of the investigations upon the alkaloid gelse- 
min are to be foundin later numbers of this journal, and in the 
“ Proceedings of the American Pharmaceutical Association.” 
HisToLoGy OF A ONE-YEAR-OLD STEM. 
A transverse section, about I mm. in diameter, of an inter- 
node at the close of the first year’s growth shows the following 
structure (Plate IX, Fig. 1). Externally are three to four lay- 
ers of cork, still covered in places by the prominently ridged 
cuticle ; next is the cortex, consisting of a zone of parenchyma 
four to five cells deep, rich in protoplasm and containing abund- 
ant chlorophyll and starch grains. A ring of large sclerotic 
