656 SUMMAEY OF CUERENT RESEARCHES RELATING TO 



aleohol and benzine, and filtered. This is also the best solvent for 

 styrax. 



Styrax and liqiiidambar, purified and prepared according to Dr. 

 van Heurck's directions, can be obtained of Messrs. Rousseau, 42- 

 44, Eue des Ecoles, Paris. 



Prof. Smith's medium, while most excellent for difficult diatoms 

 of delicate structure, is not better than styrax for ordinary diatoms 

 and preparations of histology or of insects. 



Dr. van Heurck also announces that he has discovered a colour- 

 less medium analogous to that of Prof Smith, but with an index 

 higher than liquidambar. 



Grouping Diatoms.* — J. Deby calls attention to some slides pre- 

 pared for him by MoUer, each containing many species of the same 

 genus arranged in several lines. Thus there are 72 species or varie- 

 ties of Triceratium, 60 of NitzscMa, 45 of Surirella, 38 of Epithemia, 

 &c. Such slides have, Mr. Deby considers, enormous advantages 

 over the " type-plates " from the point of view of the comparative 

 study of the species of a genus. Equally to be recommended, from 

 a scientific point of view, is, he thinks, the plan by which as many 

 species as possible from the same gathering are united in one slide. 



Quantitative Analysis of Minute Aerial Organisms.f — In the 

 reports of the Imperial German Board of Health is a paper on this 

 subject by Dr. Hesse. He employed an apparatus, which in all essen- 

 tials so corresponds with the portable aeroscope of Dr. Maddox 

 described in this Journal, III. (1883) p. 338, that it is necessary to 

 note the fact, as no reference is made to it by Dr. Hesse. Instead, 

 however, of drawing the air direct into an aeroscope and on to a thin 

 cover-glass smeared with a glutinous substance for examination of 

 the deposited matter by the Microscope, a long tube lined with a 

 layer of gelatine is used. The air is allowed to enter by an aperture 

 at one end, that most suitable being of like diameter with that of 

 the exit tube, and as it traverses the tube slowly it deposits the 

 organisms in its passage. 



According to the nature of the deposits, small colonies are deve- 

 loped in the gelatine at different parts of the tube. By employing a 

 long tube and slow traverse of air, the bacteria are deposited before 

 reaching the exit, while the fungi — mildew and spores — appeared more 

 abundant at the exit end than at the entrance. That bacteria are 

 rapidly deposited in tranquil spaces was long since shown by Professor 

 Tyndall. 



Microscopical Evidence of the Antiquity of Articles of Stone.J 

 — An action has recently been pending in New York as to the genuine- 

 ness of the collection of antiquities brought from Cyprus by Count Di 

 Cesnola and sold to the city. 



Mr. B. Braman, President of the New York Microscopical Society, 



* Journ. de Microgr., viii. (1884) pp. 230-1. 

 + MT. aus dem K. Gesundheitsamte, ii. Berlin, 188i, 



% Amer. Mon. Micr. Journ., v. (1884) pp. 14-5, from New York Times, 22nd 

 Dec, 1883. 



