1899] FRESH FACTS 65 



two being kept together by means of melted paraffine applied to the edge of the 

 common wound. The result, as regards coloration, was that while the cecropia 

 exhibited, as far as could be determined, the normal specific colours, portions of 

 the 2^'omethea wings presented the colours characteristic of only the wings of 

 cecropia. ^ 



Mosquitoes and Malaria. B. Grassi. — " La malaria propagata per mezzo 

 di peculiar! insetti" (Atti R. Accad. Lincei (Rend.) vii. (1898) pp. 23-4-240). 

 Prof. Grassi has published a second preliminary note in support of his important 

 theory that various "mosquitoes" (Anopheles claviger, Culex penicillaris, and 

 Cidejc malariae) are agents in spreading malaria. He takes account of other 



<^> ■ < v> "^ 



Pearl-Making. Louis Boutan.— " Production artificielle des perles chez 

 les Haliotis " (C. R. Ac. Sci. cxxvii. (1898) pp. 828-830). By "trepanning" 

 the shell and introducing minute spherules of nacre, Boutan was able to induce 

 the formation of " really fine pearls," which cannot be called false. 



"O <^y *0 



Pigmentation of the Mussel. Victor Faussek. — " Ueber die Ablagerung 

 des Pigmentes bei Mytilus " (Z. wiss. Zool. lxv. (1898) pp. 112-142). A 

 number of experiments show that the formation and deposition of pigment in 

 the mantle, gills, and other parts of the common mussel is not at all affected by 

 alterations in the light, but is in part regulated by the variable degree of 

 exposure to oxygenated water, taken in connection with the distribution of the 

 blood-vessels. ^ ^ _ 



*Q>. <^K •<C^>- 



Respiration of the Lamprey. E. Couvreur. — " Etude sur la respiration 

 des poissons. Mecanisme respiratoire chez les Cyclostomes " (Ann. Soc. Linn. 

 Lyon, xliv. (1898) pp. 105-109, 2 figs.) In the young lamprey, in the 

 Ammocoete stage, the respiratory movements occur about eighty times a minute, 

 mounting up to a hundred during excitement, but are occasionally sus- 

 pended for a considerable period. During inspiration the lingual piston is 

 projected, the body-walls expand, the spiracula (external apertures) are opened 

 by the relaxation of the sphincters, and the oscula (apertures into the respira- 

 tory tube) are opened by the forward movement of the piston. The water 

 then enters the branchial sacs by the spiracles and oscula simultaneously. 

 During expiration the piston retracts, the spiracles are slightly open, the oscula 

 •are closed. The water then passes out by the spiracula. When the lamprey 

 is fixed by its mouth it expires and inspires only by the spiracula, as Dumeril 

 observed long ago. Couvreur adds the interesting note that the retraction of 

 the piston corresponds to the systole, and its projection to the diastole of the 

 heart. ^ _ _ 



Syncytia in Development. W. His. — " Ueber Zellen- und Syncytien- 

 bildung. Studien am Salmonidenkeim " (Abh. K. Sachs. Ges. Wiss. xxiv. (1898) 

 pp. 401-468, 41 figs.) In this important and beautifully illustrated paper, Prof. 

 His discusses syncytia, i.e. "complexes of mutually connected histological units 

 or plasmochores, which are distinctly separated from one another by limiting 

 areas or diastemas." Their primary origin is from incomplete processes of 

 division, but they may also arise secondarily by the marginal coalescence of 

 previously distinct cells. Both types occur abundantly in the blastoderms of 

 fishes. The paper ends with the weighty statement that syncytia and pluri- 

 polar nuclear divisions, and giant-nuclei or syncaryoses, are associated 

 phenomena, always implying the occurrence of intense plasmic activity and 

 favourable nutritive conditions. 



5 — NAT. BO. — VOL. XIV. NO. 83. 



