70 G SUMMARY OF CURRENT RESEARCHES RELATING TO 



allow a stcrilizod covor-glass to fit over them. The nutrient media were 

 thin layers of gelatin or agar. By this means tlio lively movements 

 of tho bacilli were limited as to their locality, and thus became 

 accessible to continuous observation . Of course sufficient provision 

 was made for the presence of air and moisture. Geisslcr's parallel- 

 walled chamber upon which very thin layers of gelatin and agar 

 can bo spread, proved of much service For the hot stago tho Lowit- 

 Reichort modification of Strieker's stago, for which there is a special 

 condenser, was used. 



Special Criterion of Tubercle-bacilli.* — Dr. Voltolini states 

 that if cover preparations of phthisical sputum be laid in strong 

 nitric acid (1*45-1 "50 sp. gr.) before staining with the Ehrlich solu- 

 tion, the bacilli are afterwards found to have a granular moniliform 

 appearance. The author considers this a special characteristic of 

 tubercle-bacilli, as ho has not found it in any other micro-organism, 

 not even in the Lepra-bacillus. 



Application of "Ranvier's" Alcohol.t— Dr. J. H. List recom- 

 mends one-third (Ranvier) alcohol, in conjunction with 10 per cent, 

 salt solution as the best isolation medium for pavement epithelia, 

 one of its principal merits being that cells thus isolated stain 

 extremely well. Ranvier's alcohol is, however, less suitable for goblet 

 cells which are much better studied after being treated with Midler's 

 fluid or osmic acid. 



Schallibaum's Collodion.} — Mr. A. B. Lee finding it stated § that it 

 is necessary when using Schallibaum's fixation method to heat the 

 slide until the oil of cloves is driven off, writes to say that this is an 

 error, and that it is not necessary to heat the fixative to such an 

 extent, but merely until the clove oil runs easily. For this purpose 

 a water bath may or may not be used ; it is quite sufficient to hold the 

 slide for a few seconds over a spirit-lamp or Bunsen's burner, moving 

 it to and fro the while. The procedure is as safe as it is convenient. 



Imbedding with Benzol and Cutting very delicate Objects.|| — 

 Dr. A. Brass after alluding to the inconveniences attending the 

 employment of chloroform for imbedding histological preparations, 

 strongly advocates the use of benzol for this purpose. 



The stained and hardened objects are first of all immersed in con- 

 centrated alcohol, which is dehydrated by the addition of dried copper 

 sulphate. All the water having been removed from the section the 

 alcohol is passed off and the preparations covered over with pure 

 benzol. The stoppered glass vessel in which the previous steps are 

 effected, is then transferred to a water bath at a temperature of 30°, 

 and as much finely scraped paraffin added as will dissolve. After 

 being kept at this temperature for half an hour, the preparation is 

 transferred to pure paraffin which is just at its melting point. To 

 every 100 parts of paraffin about four to six parts of white wax 

 are added. Preparations the size of a pea are left in the paraffin for 



* Breslauer Aerztl. Zeitscbr., 1885, No. 15. 

 t Zeitschr. f. Wiss. Mikr., ii. (1885) p. 514. 

 X Ibid., p. 522. § Ibid., p. S71. || Ibid., pp. 300-5. 



