678 SUMMARY OF CURRENT RESEARCHES RELATING TO 



well to it, SO as to form a fluid-tight cell. Into this put four or five drops 

 of the acid ; watch its action closely when the glass has acquired an opaque 

 film, which will be in from three to five minutes ; wash it with a stream of 

 warm water ; finish with a camel-hair pencil. Eemove the wax and dry 

 the slide. The result shows crystals of silicon fluoride, which require no 

 mounting. 



Blood, permanent Preparations of. 



[Method tiiught in Heidelberg.] The Microscope, VII. (1887) p. 115. 



Bramwell, K. — Process for the detection of micro-organisms in nerve-tissue. 



Edin. Med. Journ., 1886, p. 324. 

 Cabtellaenatj, J. M. de. — Procedes pour I'Examen microscopique et la Conserva- 

 tion des Animaux a la Station zoologique de Naples. (Methods for the microscopical 

 examination and the preservation of animals at the Naples Zoological Station.) 



Journ. de Microgr., XI. (1887) pp. 183-6, 215-7, 447-53. 

 Fellows, 0. S. — Collecting, dissecting, and mounting Entomostraca. 



Proc. Amer. Soc. Micr., 9th Ann. Meeting, 1886, pp. 186-8. 

 Martin, L. J. — Petroleum Spirit as a Plant Preservative. 



[Recommends petroleum spirit (boiling from 25°-45° 0.) for preserving plants 

 iiiteniled for the stiidv of chemical constituents.] 



Bot. Gazette, XII. (1887) p. 42. 

 Miles, J. "W. L. — The capturing, killing, and preservation of Insects for microscopical 

 purposes. Trans, and Ann. Eep. Manchester Micr. Soc, 1886, pp. 80-1 . 



Paekes, R. — The preparation of Poraminifera from common chalk. 



Trans, and Ann. Eep. Manchester Micr. Soc, 1886, p. 21. 



(3) Cutting, including: Imbedding and Microtomes. 



Ryder's Paraffin Imbedding Apparatus.* — Prof. J. A. Eyder describes 

 a new paraffin imbedding apparatus which he has designed. 



Those who have had much experience in imbedding in paraffin are 

 aware of the difficulties and risks which attend the imbedding of delicate 

 objects on account of the danger of overheating the imbedding mass. The 

 trouble with thermostats, or heat-regulators, is that they get out of order 

 and give trouble, apart from the difficulty which arises from the variations 

 in the pressure of the gas in the pipes which supply the burners, and which 

 is entirely beyond the control of most forms of the thermostat. To avoid 

 this, Dr. C. S. DoUey, of the Biological Department of the University of 

 Pennsylvania, began a series of experiments with copper bars, which were 

 heated at one end by means of a Bunsen burner, so that the heat conveyed 

 by conduction to the remote end of the bars gradually diminished in in- 

 tensity, because of its being constantly radiated into the surrounding air, 

 according to well-known laws stated in the text-books on physics. It was 

 found that, with the room at an approximately constant temperature, there 

 was a point along the bar, at a certain constant distance from its heated 

 end, where the temperature of 55° C. could be maintained, and where, if 

 there was placed a copper cup filled with hard paraffin, the latter could be 

 kept just at the point of fusion for a long time without endangering the 

 objects to be imbedded. These results showed that it was possible to 

 utilize an apparatus of this type for imbedding purposes. 



This led the writer to begin a set of experiments with a very simple 

 modification of the foregoing type of apparatus, with the object of getting 

 rid of the usual water-bath entirely in the process of imbedding, and to 

 also use the paraffin itself as a means to indicate how far away from the 

 source of heat it would be safe to allow an object to remain while it was 

 being saturated. 



The object was effected in the following manner : — A triangular sheet 



» Amer. Naturalist, xxi. (1887) pp. 597-600 (1 fig.). 



