40 QUARTERLY CHRONICLE. 



Hum. By the existence of this structure, he thinks, may be 

 reconciled the somewhat conflicting vicAvs of anatomists re- 

 specting the structure of the conjunctiva. By it he also 

 explains the aj^pearances which have induced Henle to 

 imagine that it was furnished with innumerable glandular 

 follicles, inasmuch as in vertical sections of the membranaB 

 the appearance afforded by the deeper furrows is precisely 

 that of mucous follicles. Sections parallel with the surface 

 are requisite to show the true structure. 



8. "Description of a Gas-Chamber for 3Iicroscopical pur- 

 poses." by Dr. S. Strieker. — It is often desirable to be able 

 to examine certain objects exposed to various gases, and also 

 to be able to pass a galvanic current through them or the 

 fluid in which they are immersed ; and it may be added that 

 an apparatus suitable for these purposes might be made 

 available for the application of various chemical reagents to 

 objects contained in a close chamber under the microscope. 



These objects apjiear to be very ingeniously and, he says, 

 comfortably carried out by Dr. Strieker's contrivance, which 

 may be thus briefly described with the aid of a woodcut : 

 |R In the middle of a piece of thickish plate glass of suitable 

 dimensions (a) a circular groove (r) is cut, and from this a 





■V- 







^- l -TVgz ^J Cl 



straight furrow {g, g), of the same depth, to each end. In 

 each of these furrows is placed a slender metallic tube (f and 

 f ), preferably of platinum, and each having at its extremity 

 a small bulbous enlargement, for the purpose, Avhen needed, 

 of affixing caoutchouc tubes. These metallic tubes are ce- 

 mented into the furrows by means of shellac or other suitable 

 cement, and thus serve as the sole means of communication 

 with the circular furrow (>•). The whole surface of the glass 

 is now covered either with a layer of paper or of some var- 

 nish, but in either case has a circular space left open in the 

 centre {a, a). The object of the paper or other covering is 

 to keep the covering glass {b, b, b, b) at a suitable distance 

 from the central circular portion of glass (o) upon which the 

 object to be examined is placed. The mode of using this 



