BIOLOGY. 297 



action of sunlight. Like chloroform, it in some instances pro- 

 duces vomiting. 



It acts evenly on the respiration and circulation, accelerating 

 or retarding both together; this is a valuable property, as a dis- 

 turbance of the balance between these two systems is one of dan- 

 ger; it probably owes this to the equality of its diffusion through 

 the nervous centres. Compared with chloroform, it requires 1 

 drachm to 40 grains or minims of the latter; but when the narco- 

 tism is well established it requires less to sustain it and less fre- 

 quent repetition. Experiments on animals of the same age and 

 kind, exposed, under similar conditions, to equal values of the 

 vapors of chloroform, tetrachloride of carbon, and bichloride of 

 methylene, show that the resistance to death will be as 14 to 5 in 

 favor of the bichloride against the tetrachloride, and as 14 to 9 

 against the chloroform. — Med. Times and Gazette. 



THE SPLANCHNOSCOPE. 



To the ophthalmoscope of Helmholtz, by which the depths of 

 the eye may be explored, — the laryngoscope of Czernak, which 

 reveals the condition of the air-passages, — and the urethroscope 

 of Desormeaux, disclosing the secrets of the urinary canals, — 

 must now be added the splanchnoscope, rendered of practical util- 

 ity by Dr. Millot of Kiew, by which the human body may be made 

 transparent by light developed within its cavities. By means of 

 the Geisler tube, rendered luminous by electricity passed in a 

 vacuum or through various gases, giving light without heat, this 

 invention has been made possible. Dr. Millot's instrument is 

 Middledorf's improved Geisler tube. He has introduced it by an 

 oesophageal probe into the stomachs of a dog and cat, and enabled 

 spectators to see distinctly every detail of the organ ; in the same 

 way the internal membrane of the human viscera has been ren- 

 dered perfectly visible. The instrument, when further improved, 

 will doubtless lead to very important physiological results. 



ON THE TRANSMISSION OF LIGHT THROUGH ANIMAL TISSUES. 



At the 1868 meeting of the British Association, Dr. Richardson 

 exhibited a lamp which he had constructed for this purpose. He 

 believed that the first idea that such transmission could be effected 

 was given in Priestley's work on electricity. Of late years research 

 had been made with the microscope in the transparent web of the 

 foot of the frog, and last vear Dr. Mackintosh had shown that 

 young trout could be used experimentally, they being sufficiently 

 transparent for the investigation of the action of various poisonous 

 substances. The suggestion of Dr. Mackintosh had been acted 

 upon by the author, and the motion of the heart and of the respira- 

 tion had been observed by direct ocular demonstration while those 

 orcrans were under the influences of various bodies belono;'ing to 

 the ethyl and methyl series. This research had led Dr. Richard- 



