Dr. A. Waller's Researches on the Organ of Vision. 517 



actiou, and a chlorine compound resulted, which, when purified and 

 analysed, gave numhers agreeing perfectly with Cjg H22 Cl,„ corre- 

 sponding to a hydrocarbon, C.,g H.,,^, a formula with which the ana- 

 lysis of the original hydrocarbon was perfectly consistent, although 

 its boiling-point pointed rather to a lower formula. 



Action of Oxidizing Agents on the Hydrocarbons. 



By the action of boiling diluted nitric acid, continued for many 

 months, on the hydrocarbons not acted upon by concentrated 

 sulphuric and nitric acids, oxidation gradually takes place, and a 

 great variety of acids are produced, among which we have isolated 

 succinic acid, and several others belonging to the series €„ Hn_„ O^. 



Oxalic acid, the lowest term of this series, could not be traced ; 

 there occurs, however, in these products several of the volatile acids 

 of the acetic acid series, but in very small quantities. The rough 

 distillates obtained from the Burmese naphtha, when treated in the 

 same manner, yield, in addition to the foregoing, several aromatic 

 acids, derivatives of the benzole series and its isomers, differing however 

 from any acids at present known. Other oxidizing agents have been 

 employed by us, but not with such marked results. 



November 20.— Dr. Miller, V.P., in the Chair. 

 The following communications were read : — 



" Experimental Researches on the Organ of Vision. — Part I. Mi- 

 croscopic Examination of the Circulation of the Blood in the Vessels 

 of the Iris and of the Choroid Membrane, &c." By Augustus 

 Waller, M.D., F.R.S. 



In a former paper on the section of the optic nerve, the author de- 

 scribed a process of producing temporary extrusion of the eyeball from 

 the socket in the living animal. Although adopted in the first instance 

 merely for the jjurpose of dividing the optic nerve de visu with as 

 little injury as possible, the same means of exjiosing the eyeball may be 

 advantageously employed for studying various other points relating to 

 the phvsiology of the eye. In the first place, as the eyeball is so much 

 protruded from the orbit, Kepler's experiment on the ej'c removed 

 from the body, showing that external objects form inverted images 

 on the retina, maybe performed on the living animal. For this purpose 

 it is merely requisite to place a bright object obliquely before the 

 pupil, a candle for instance, in order to ascertain that a reversed image 

 of it is formed on the opposite side of the eye. On a young rabbit 

 placed in a dark room, particularly if an albino animal is used, the 

 inverted image of the candle, although having to traverse the choroid, 

 the sclerotic and the muscular parts, is perceived bright, and tole- 

 rably well defined. When this bright spot is examined with a lens 

 or a compound microscope, it is found to be sufficiently illuminated 

 to allow of the examination of the motion of the globules of the 

 blood. On the young guinea-pig the same may be still more easily 

 examined, but it is particularly the albino rat or surmidot {Mus 

 decumanus) that the author has found most suitable for these obser- 



