422 SUMMARY OF CURRENT RESEARCHES RELATING TO 



the stomach, which commencing at the indiarubber balls K passes into 

 the main tube at L and is continued to L' where there is a small 

 aperture. 



The optical apparatus consists of a prism and an objective at E 

 (the prism being right-angled and acting as a reflector to transmit the 

 rays from the side of the instrument up the tube), a second prism at 

 the bend at F, and an eye-piece at G. To prevent the glass plate at 

 B from being smeared whilst the instrument is passed down the 

 oesophagus a metal shutter H slides over it and can be drawn back by 

 moving the collar at J. 



The fact is enforced in italics that the instrument can be intro- 

 duced into the bottom of the stomach without difficulty, and fig. 69 

 is given in illustration of the statement ; another figure showing the 

 advantage of the bent end in allowing different parts to be illuminated 

 and observed by simply rotating the tube, the stomach being distended 

 to facilitate the excursions of the tube. The author's pamphlet con- 

 tains not only a very full description of the instrument, but minute 

 directions for its use. 



Dr. T. Oliver describes * a successful experiment of examining the 

 interior of a patient's liver by one cf the small Swan incandescent 

 lamps described by Mr. Steam ante, p. 29. The apparatus used was 

 an electro-plated brass tube 9i in. by 11-1 6ths in., closed at the lower 

 end by glass, down which was inserted a narrow cylinder carrying a 

 lamp and wires. Mr. J. B, Payne (a Fellow of this Society), who 

 devised the arrangement, considers it to be much simpler than Leiter's 

 platinum wire as it gives a perfectly pui-e light and developes less 

 heat. He says " a Swan's electric lamp is used — the filament of 

 which is carbon, and rendered incandescent by means of battery 

 power. It is hermetically sealed in a glass shade ; and water, con- 

 veyed to and fro through very small brass tubes, is made to circulate 

 round the lamp. The light from this lamp is perfectly pure, and 

 exhibits the condition of things in their true and natural colour. For 

 prolonged observation I should prefer to use either a Grove's or 

 Bunsen's battery, but in the demonstration just referred to, four cells 

 of a modified Leclanche battery were employed and answered ad- 

 mirably. It is advisable to have as great a pressure as possible for 

 the water supply, so as to insure perfect circulation, and for this I 

 suspended from a hook fixed near the ceiling of the room a tin can 

 containing water, connecting it with the brass tubes by means of 

 lengths of indiarubber tubing." 



Cobweb Micrometers. I — Mr. G. F. Dowdeswell prefers a cobweb 

 micrometer which has the second web movable instead of being fixed 

 as in the usual form. This both saves time and promotes accuracy, as 

 when only one web is movable it is almost impossible, by means of 

 the mechanical stage, to bring an object into exact contact with the 

 fixed web, which is done at once with ease and certainty by the second 

 movable one. 



♦ Brit. Med. Jouin., 1883, Jan. 27. 



t Quart. Journ. Micr. Sci., xxiii. (1883) p. 337. 



