566 SUMMAKY OF CUREENT EESEARCHES RELATING TO 



Centrosome and Blepharoplast.* — Prof. F. K. Studnicka has studied 

 the little swelling (blepharoplast, basal piece) which occurs at the base 

 of the cilia in the ciliated cells of animals and the spermatozoids and 

 swarm-spores of plants. The swelling has been homologised with the 

 centrosome, but the author finds that swelling and centrosome may co- 

 exist, e.g. in Petromyzon fluviatilis and Salamandra maculata. The fact 

 that in the non-motile ciliated cells of the gut in Ascaris the basal piece 

 is very slightly developed, confirms the view that it is the motor centre 

 for the cilia. In consequence, the existence of the blepharoplast in the 

 spermatozoids of certain of the higher plants cannot be taken as evidence 

 that the vegetative cells of those plants must contain a centrosome ; for 

 as blepharoplast and centrosome may coexist, it is reasonable to suppose 

 that the former may appear in a cell which does not contain a centro- 

 some and never possessed such a structure. 



Function of Nucleus.f — M. Henri Stassano finds that the cells of 

 the vascular endothelium manifest a strong affinity for mercury and 

 other poisons introduced into the circulation, and believes that this is 

 effected by the nucleus, by virtue of its contained nucleins which form 

 compounds with metals and bases analogous to salts. He arranges the 

 evidence] in support of this thesis under five heads : — (1) Leucocytes, 

 which are very rich in nucleins, display a strong affinity for metals. 

 (2) In young dogs the endothelial cells contain granulations shown by 

 Kowalewsky to present the characters of nuclear granulations, and the 

 author finds that the organs of such young dogs absorb more mercury 

 than equal weights of the organs of adult dogs, in which the granula- 

 tions are absent, under identical experimental conditions. (3) It has 

 been shown that the proportion of nuclein contained in an organ depends 

 upon the number of cell-nuclei present, and the author's experiments 

 show that the amount of mercury absorbed by an organ depends upon 

 the amount of nuclein present in it. (4) The non-nucleated red blood- 

 corpuscles of mammals are the only cellular elements which do not 

 absorb mercury. (5) An intravenous injection of methyl-violet 

 reduces considerably the absorption of mercury by the cells of the vas- 

 cular endothelium. With this may be compared the fact that cells sub- 

 jected for a prolonged period to such reagents as osmic acid refuse to 

 take up stains subsequently. Indeed, the familiar affinity of the nucleus 

 for basic stains may be regarded as in itself a proof of the author's 

 position ; and if the nucleins be, as it were, previously saturated by a 

 metal or an acid, then the nucleus will no longer take up a stain. 



New Theory of the Nucleus. % — J. Kunstler has been impressed, in 

 the course of his studies on Bacteriaceae (e.g. Bacterioidomonas sporifera 

 Kunstler), with the resemblance between spores and nuclei ; and ventures 

 the suggestion that the nucleus of the cell may be the result of the 

 transformation of a sporogenic bud, or the vestige of a reproductive pro 

 cess diverted from its primitive end. 



Structure of Nerve-Cells.§ — C. Martinotti and V. Tirelli have applied 

 the method of photomicrography to the study of the nerve-cells of the 



* S.B. Bohm. Ges., xxxv. (1899) 22 pp. (1 pi. and 4 figs.). See also Bot. Cen- 

 tralbl., lxxxii. (1900) pp. 374-5. t Comptes Rendus, cxxx. (1900) pp. 1780-3. 

 t Tom. cit., pp. 1416-8. § Anat. Anzeig., xvii. (1900) pp. 369-80 (1 pi.). 



