138 NOTES AND MEMOEANDA. 



now fuse together in pairs, producing a similar figure to the last, but 

 coarser. 



10. The two daughter-nuclei (the two halves of the barrel-form) 

 separate from one another, and each assumes a star-shape. 



11. The rays of each star unite and form loops, the wreath-form 

 being the result. 



12. The filaments of the wreath become thicker and more closely 

 meshed. 



13. As the process of division approaches completion, the coils 

 become finer, and the basket-form is produced. 



14. Finally, the ordinary intranucleolar network is produced, 

 marking the completion of the division process and the entrance of 

 the nuclei into a state of quiescence. 



Picro-carmine for Cell-nuclei. — In the Eeport published last 

 August of the Proceedings of the International Congress of Botanists, 

 held at Amsterdam in 1877, is a paper by M. Treub, who drew 

 attention to the use of picro-carmine as a reagent for this purpose. 

 His first step is to kill the cells by absolute alcohol, according to the 

 directions of Strasburger. After making some sections of tissues 

 which had remained in the liquid, the prejiarations are placed in a 

 1 per cent, solution of picro-carmine, for a time varying from four to 

 twenty hours ; they are then shaken in distilled water in order to 

 dissolve the picric acid, and are placed in a mixture of glycerine and 

 distilled water, which is gradually replaced by pure glycerine con- 

 taining 1 per cent, of formic acid. After this treatment the nuclei 

 almost always assume a fine red colour, whilst the protoplasm remains 

 entirely uncoloured, which enables the slightest changes which take 

 place in the nuclei to be at once distinguished.* 



Influence of the different Colours of the Spectrum on Animals 

 and Plants. — 1. Animals. — Observations on the influence of the 

 different coloured rays of solar light upon the nutrition of plants 

 have been more numerous than those on the development of animals. 

 M. Beclard in 1858 experimented with eggs of Musca carnaria under 

 different coloured glasses, and found that the eggs developed very 

 unequally, those of the violet and blue rays developing most rapidly, 

 and in the green least. 



M. E. Yung t has for three years experimented at the University 

 of Geneva with the eggs of Bana temporaria, JR. esculenta, Salmo 

 trutta, and Lymnea stagnalis. 



The eggs were placed directly after fecundation in vessels which 

 were plunged in solutions coloured respectively violet, blue, green, 

 red, and white, one being also placed in the dark. 



The general results were as follows : — 



(1) The different coloured rays of solar light act in a very 

 different manner on the development of the eggs of the above 

 animals. 



(2) Violet light quickens the development in a very remarkable 



* 'Bull. Soc. Bot. de France,' vol. xxv. (1878) p. 129. 

 t 'Comptes Reiidus,' vol. Ixxxvii. (1878) p. 998. 



