288 



SUMMARY OF CURRENT RESEARCHES RELATING TO 



made, including those of Strieker* who converted his putty cell so as to 

 make it available for gas, by the simple process of introducing two small 

 glass tubes through the putty, and a second form, with a mercurial 

 valve, which he | adapted from Kiilinc. llarless used two glass slides, 

 the sides of which were cemented together so as to keep them about 

 0-5-1 mm. apart; the two ends were fixed in pieces of cork, and two 

 tubes passed through the corks communicating with the space between 

 the slides. Kiihne's was a small glass box into which two tubes were 

 led. Huizinga } used a glass tube with a bulb in the centre, ground off 

 above and below so as to have two openings, both of which were closed 

 by cover-glasses, the object being placed on the under side of the upper 

 one. Ileidenhain's § was a square metal box with apertures closed by 

 glass plates. T. W. Engelmann's \\ was also similar. 



The following forms have not yet been described in English : — 

 Buttcher % suggests the apparatus shown in fig. 46, consisting of a 

 short pieco of tubo C, and two tubes A and B, all cemented to a slide. 



Fig. 46. 



In Streclcers ** (fig. 47) a hollow space with a groove A is cut 

 away from a thick glass plate, and is surrounded by a glass ring of pro- 



Fig. 47. 



portionate height cemented to the plate. At two opposite points of the 

 latter, and along the diameter of the plate, are shallow grooves in which 

 are cemented the glass or metal tubes B and C extending as far as the 

 groove A ; one of these is connected with tho gas reservoir by means of 

 a guttapercha tube. The object is suspended in the central space D. 



* 'Manual of Human and Comparative Histology,' tranal. by Power, 1870, 

 pp. viii.-ix. (1 nv.)- t Op. cit., pp. xi.-xii. (1 fig.). 



t Med. Centralbl., 1867, p. 675. 

 § Thanhoffer's Das Mikroskop, 1880, pp. 86-7. 

 || Jenaisch. Zeitschr. f. Med. u. Naturwiss., iv. (1868) pp. 331-3. 

 i Dippel's Das Mikroskop, 1882, p. 603 (1 fig.). ** Ibid., pp. 663-4 (1 fig.). 



