ZOOLOGY AND BOTANY, MICROSCOPYj ETC. 539 



nigrosin and logwood (Kleinenberg's) should be used in weak solu- 

 tions, and allowed to operate for a long time. 



The most preferable staining reagents are considered to be car- 

 mine and picro-carmine, which may be used singly or together. As 

 mounting media, Cattaneo recommends glycerin and oil of cloves. 



Preparing Euglena.* — Cooked turf, steeped in nutrient salt-solu- 

 tion, is advocated by Dr. G. Klebs as a good substratum for the culti- 

 vation of Euglena and Algae. Carminic acid is employed for killing 

 the cilia. 



The membrane of Euglena viridis is almost entirely consumed by 

 pepsin in twenty-four hours ; that of Phacus is apparently unchanged 

 after days. One ingredient is removed from the membrane of Euglena 

 by the pepsin, while another remains behind in the original structure. 

 The first belongs to the group of albuminoids, and the other must be 

 considered as a cellular membrane substance. 



Euglena can be kept for many weeks in nigrosin and indigo-car- 

 mine without taking up the colouring matter. Living specimens of 

 E. spirogyra have been successfully stained with logwood. The whole 

 membrane became dark blue, after first treating it with • 5 per cent, 

 solution of sodium chloride, to which 1 per cent, chromic acid was 

 afterwards added. After several seconds the Euglena was washed 

 and placed in a watery solution of logwood. The membrane can also 

 be stained with carmine, eosin, and anilin-blue. With sulphuric acid 

 it becomes yellow or brown. The whole membrane becomes yellow 

 or nearly black when impregnated with hydrated oxide of iron. 



It has not been found possible to separate the cytoplasm from the 

 membrane even when a saturated solution of sodium or calcium 

 chloride is applied. ,The separation is most easily effected by 

 mechanical pressure, or by alcohol, best when the Euglena has been 

 previously killed. 



By the application of 10 per cent, sodium chloride the principal 

 vacuole breaks up, and its water is absorbed. Alkaloids produce an 

 enormous dilatation. With sulphate of quinine, only in FJiacus 

 pleuronedes and P. pyrum is a slight increase of the principal vacuole 

 observed ; but this is not the rule. 



Preparing the Bacillus of Syphilis, f — In sixteen cases of 

 syphilis Dr. S. Lustgarten has found characteristic bacilli in the 

 initial lesion, lymphatic gland, papules, and products of the tertiary 

 stage. 



Sections hardened in alcohol are stained in Bhrlich-Weigert's 

 gentian-violet from 12-24 hours at the ordinary temperature, and 

 then for two hours at 104° F. They are then washed in absolute 

 alcohol for several minutes, and transferred on a glass or platinum 

 needle to a watch-glass containing about 3 c.cm. of a 1^ per cent, 

 aqueous solution of permanganate of potash, in which they remain 

 about ten seconds. A brown precipitate forms in the fluid and on the 



* Untersuch. aus d. Botan. lastit. zu TiibiugeD, i. (1883) pp. 233-62. 

 t Wiener Med. Jahrb., 1885. 



