642 
SUMMARY OF CURRENT RESEARCHES RELATING TO 
One main purpose of lime salts appears to be the removal of the 
poisonous oxalic acid ; and it is probable that the framework of the 
chlorophyll-bodies and of the nucleus consists of combinations of calcium 
with plastin and nuclein. Magnesia is a much weaker base than lime, 
and its salts are more easily decomposed; hence the assimilation of 
nitrogen and sulphur is much more easily effected from magnesium than 
from calcium salts, and from these more easily than from potassium or 
sodium salts. One of the useful purposes served by magnesium salts is 
the formation of magnesium phosphate, which gives off with great 
readiness a portion of its phosphoric acid, and thus greatly facilitates 
the formation of nuclein, plastin, and lecithin. Neutral oxalates are 
poisonous to the higher plants and to algae, but not to the lower 
fungi. When calcium salts are not present, magnesium salts are 
poisonous to all chlorophyllaceous plants ; but, when accompanied by 
a sufficient quantity of calcium salts, they display no trace of this 
poisonous property, and perform their nutritive function as a carrier of 
phosphoric acid. 
y. General. 
Myrmecophilous Oak-galls.* * * § — According to Prof. E. Rathay, the 
galls of Cynips calycis, produced on Quercus pedunculata , attract numbers 
of small ants in consequence of their viscid secretion, and he believes 
that they are in this way advantageous to the tree, the ants killing 
quantities of caterpillars and others of its natural enemies. The value 
of this protection is illustrated by the tact that the inhabitants of a single 
ant’s nest may destroy in one day upwards of 100,000 insects. 
Micro-organisms and Insectivorous Plants.f — From observations 
made on Pinguicula vulgaris , Prosera rotundifolia and longifolia , Dionsea 
muscipula , and Nepenthes Mastersi, Herr N. Tischutkin concludes that 
the solution of albumen by their sap is not due to any peptonizing 
substance contained in solution in it, but to the activity of the micro- 
organisms, always present in the sap of the mature plant, and derived 
from the air, the bodies of insects, &c. For the development of these 
microbes the peculiar secretion of insectivorous plants furnishes a very 
favourable pabulum. The secretion of young unopened pitchers of 
Nepenthes has no peptonizing property. 
Nectar of Poinsettia.J — According to Mr. W. E. Stone, the nectar of 
Poinsettia pulcherrima consists approximately of cane-sugar 11*23 per 
cent., glucose 57*79 per cent., water 30*98 per cent. 
E. CRYPTOGAMIA. 
Cryptogamia Vascularia. 
Male Prothallium of the Rhizocarpeae.§ — Herr W. Beliajeff has 
studied the male prothallium which proceeds from the microspore in the 
genera Salvinia , Azolla, Marsilea , and Pilularia. Its structure and 
* SB. K. K. Zool.-Bot. Gesell. Wien, xli. (1891) pp. 88-93. 
f Arb. St Petersburg Naturf.-Gesell. (Bot.), 1891, pp. 33-7. SeeBot. Centralbl., 
1. (1892) p. 304. X Rot. Gazette, xvii. (1892) pp. 192-3. 
§ ‘ Ueber d. mannlichen Prothallien d. Rhizocarpeen,’ Warschau, 1890, 86 pp. 
and' 5 pis. See Bot. Centralbl., 1. (1892) p. 327 (3 figs.). 
