ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 549 



But tho author does not regard them as true centrosomes ; they are 

 rather specialised masses of kinoplasm, perhaps rudimentary centro- 

 somes. 



Lignification of the Cell- wall.* — For the determination of the 

 degree of lignification of the cell-wall, P. Sonntag prefers chemical 

 analysis to the test usually employed, the intensity of staining with 

 phloroglucin and hydrochloric acid. By analysis you get a percent- 

 age of 58*7 of ligneous substances in cocoa-fibre, and 59 in the wood 

 of Garyota. With increase of lignification the capacity of the mem- 

 brane for swelling diminishes. The swelling always takes place at 

 right angles to the direction of the pores. The firmness of wood 

 depends not only on the degree of lignification, but also on the size 

 and number of the pores. The autumn wood of Pinus sylvestris and 

 Abies pectinata, which has only small pores, possesses a degree of firm- 

 ness represented by 45 ■ 4 and 45*5 respectively; while the spring wood 

 of the same trees, which has numerous large pores, has a firmness of 

 only 19-65 and 20*0 respectively. 



(2) Other Cell-contents (including: Secretions). 



Nitrogenous Contents of Green Leaves. f — E. Winterstein finds the 

 nitrogenous constituents of green leaves to correspond closely in their 

 reactions to those of fungi. In the residue which remains after treating 

 pulverised green leaves with dilute and 1 p.c. alkali, the proportion of 

 nitrogen was found to vary between 0*60 p.c. (Lolium perenne) and 

 6 "20 p.c. (Spinacea oleracea). 



New Chromogen producing a Red Pigment.^ — Prof. H. Molisch 

 finds in Schenckia blumenaviana, a Rubiaceouss plant from Brazil, a 

 carmine-red pigment, which, however, appears only when the part of 

 the plant in question is wounded or withered. It is probably the result 

 of the action of an enzyme on the chromogen. It was found in the 

 root, leaf, and stem, as well as in the flowers, and colours not only the 

 cell-contents, but also the cell-wall. The chromogen is not rubian, and 

 the pigment is not identical with alizarin, purpurin, anthocyan, phyco- 

 erythrin, or any other known red pigment of plants. 



Leptomin.§ — Prof. S. H. Vines objects to this term, proposed by 

 Eaciborski for the substance found by him as a widely distributed cell- 

 content in the vegetable kingdom, inasmuch as it has no special con- 

 nection with sieve-tissue. He also dissents from Raciborski's theory || 

 that it plays the part of haemoglobin in the animal kingdom as a carrier 

 of oxygen. Prof. Vines gives also the result of experiments which 

 appear to show the very partial distribution of this substance in fruits, 

 oils, and seeds. 



(3) Structure of Tissues. 



Effect of Low Temperatures on Meristematic Tissues.^"— B. Nemec 

 states that if turgescent root-tips of Allium Cepa are transferred directly 



* Ber. Deutsch. Bot. Ges., six. (1901) pp. 138-49 (1 pi.), 

 f Tom. cit., pp. 326-30. J Tom. cit., pp. 149-52. 



§ Ann. of Bot., xv. (1901) pp. 1S1-3. Cf. this Journal, 1S99, p. 44. 

 || Cf. this Journal, 1S98, p. 551. 

 ■f SB. k. Boehm. Ges.Wiss., 189a, No. 12. See Bot. Centralbl., lxxxvi. (1901) p. 237. 



Oct. 16th, 1901 2 p 



