ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 
551 
of the antherozoids, but one each at the polar and antipolar sides of 
the nucleus in the primary mother-cells of the antherozoids, before their 
division. During karyokinesis the stainable body was not seen in the 
form of a centrosome, from which the achromatin-threads proceed. It 
is possible that, in the karyokinetic division of the nucleus, a large 
number of centrosomes may be found on the poles of the nuclear spindle, 
which subsequently unite to form one of the stainable bodies. The 
author has observed a number of the small stainable granules on the 
broad polar ends of the nuclear spindle in the embryo-cells of Larix. 
Reaction of Protoplasm to Thermal Irritation.* — The result of a 
series of experiments on the effect of different temperatures on the 
activity of protoplasm leads Dr. K. L. Schaefer to the law that at tem- 
peratures between 10° and 31° C., the sensitiveness increases very nearly 
in geometrical proportion with arithmetical increases of temperature. 
(2) Other Cell-contents (including Secretions}. 
Leptomin, a new Cell-content of Leptome.f — In the leptome of a 
large number of plants Herr M. Raciborski finds a new substance, to 
which he gives the name leptomin , the function of which appears to be 
the conveyance of oxygen. It occurs especially in the sieve-tubes and 
laticiferous vessels, but also in many parenchymatous cells. 
Leptomin is destroyed in solution by short heating to 95° C. ; it is 
soluble in water and glycerin, insoluble in alcohol ; in the dry state it 
is an amorphous wh\te powder, which is not attacked by dilute alkalies, 
but is destroyed by dilute acetic or picric acid. A solution of guaiacum- 
resin with addition of hydrogen peroxide turns blue in the presence of 
leptomin, as in the presence of haemoglobin or haemocyanin. In the life 
of vascular plants leptomin appears to play a part analogous to that of 
haemoglobin in the higher or haemocyanin in the lower animals, facili- 
tating, as a substance rich in oxygen, the internal respiration, i.e. an 
interchange of oxygen between the sieve-tubes, laticiferous vessels, and 
other cells in which it is contained, and the surrounding tissues. 
A list of the plants in which leptomin has been found is given, 
including Gymnosperms and Vascular Cryptogams. Its presence was 
detected in every vascular plant examined, but not in fungi ; it was 
found in parasitic, saprophytic, and aquatic flowering plants. 
Oxydases and the Guaiacum Reaction.}: — Herr J. Griiss confirms his 
previous statement that an intense blue stain is produced in the phloem 
by guaiacum-hydrogen -peroxide ; also that of Raciborski of the presence 
in the leptome of the hypothetical substance which he calls leptomin. 
His experiments lead him to the conclusion that the substance which 
causes this reaction is in a transitional condition in the walls of the 
vessels. 
He finds three catalytic enzymes, corresponding to the three dia- 
stases, secretion-diastase, translocation-diastase, and cytase, and dis- 
tinguished from one another by their behaviour when heated. The 
enzyme of Penicillium is not a diastase. 
* Flora, lxxv. (1898) pp. 135-40. 
t Per. Deutsch. Bot. Gesell., xvi. (1898) pp. 52-63, 119-23. 
X Tom. cit., pp. 129-39. Cf. this Journal, 1896, p.652. 
