224 
SUMMARY OF CURRENT RESEARCHES RELATING TO 
(2) Other Cell-contents (including: Secretions). 
Plastids.* — According to M. R. Chodat, all trophoplasts (chloro- 
plasts, chromoplasts, and leucoplasts) have nearly the same structure, 
consisting of a colourless stroma, permeated by irregular lacunae; 
while slendei’er prolongations or transverse links of the stroma project 
into the lacunae, and subdivide them. The plastids have no special 
membrane ; the outermost layer is the continuous substance of the 
stroma itself. When a chromoplast is transformed into a chloroplast, 
it is not its structure that undergoes a change, but only the pigment. 
This covers the inner wall of the lacuna without filling it up, and the 
dark colour of the coating is simply the result of shadow. Schimper’s 
“ crystalloids ” have the same spongy structure as the plastids. Specially 
good subjects for observation are furnished by the chlorophyll-grains in 
the pseudo-bulb of Calanthe Sieboldi, and the chromoplasts in the meso- 
carp of the fruit of Capsicum chilense. 
Aggregations of Proteid in Euphorbia.f — Mr. R. E. Fry describes 
60me remarkable spherical aggregations in some of the cells of the 
stem of Euphorbia splendens, especially in the parenchyme immediately 
surrounding the vascular bundles ; the micro-chemical reactions showed 
these bodies to consist of coagulated masses of proteid. In the fresh 
state the proteid occurs in various forms, — either distributed throughout 
the cell-contents as a fluid, or in finely divided granules, or in various 
crystalloid forms. The distribution of these bodies in the stem, viz. in 
the inner layers of the cortex just outside the hast, in the medullary rays, 
and in the pith just within the wood, as well as experiments on growing 
plants, indicate that the proteid is used as reserve nitrogenous material, 
corresponding to starch among the carbohydrates. Similar bodies were 
observed in Euphorbia Bojeri, but not in any other latex-containing 
plant belonging either to the Euphorbiaceae or to any other natural 
order. 
Raphides in the Embryo. J — Dr. H. Micheels records the presence 
of raphides of calcium oxalate in the embryo of two species of palm, 
Ptychosperma Alexandra and a Caryota. 
Formation of Crystalloids in branches of the Potato.§— Investi- 
gating the nature of a disease which has caused great destruction of the 
potato crop in parts of Tyrol, Herr E. Heinricher found that it is 
accompanied by an enormous accumulation of proteid crystalloids in the 
low r er part of the stem. This appeared to be the result of the very wet 
season, which had caused rotting of the roots and consequent failure to 
produce tubers. The proteinaceous food-material which should have 
been employed in the formation of the tubers remained stored up in the 
leafy shoots. Their principal seat was the cortical parenchyme and the 
phloem of the vascular bundles. 
Diastase in Pollen, [j — Prof. J. E. Green records the occurrence of 
diastase in the pollen-grains of Helianthus, Lilium, Gladiolus, Anemone, 
* Arch. Sci. Phys. et Nat., xxv. (1891) pp. 244-8 (1 ph). 
t Ann. of Bot., v. (1891) pp. 413-8 (1 pi.), 
t Bull. Acad. Roy. Sci. Belgique, xxii. (1891) pp. 391-2. 
§ Ber. Deutscb. Bot. Gesell., ix (1891) pp. 287-91 (2 figs.). 
|| Ann. of Bot., v. (1891) pp. 511-2. 
