1890.] Development of Ciliary or Motor Oculi Ganglion. 287 



2\ (water) = 39*2, 2\ (saponine) = 39'5, 

 h (water) = 30' 5, h (saponine) = 207. 



Thus, although the capillary heights differ considerably, the 

 tensions at the first moment are almost equal. In this case then, as 

 in that of soap, there is strong evidence that the lowered tension is 

 the result of the formation of a pellicle. 



Though not immediately connected with the principal subject of 

 this communication, it may be well here to record that I find saponine 

 to have no effect inimical to the rebound after mutual collision of jets 

 containing it. The same may be said of gelatine, whose solutions 

 froth strongly. On the other hand, a very little soap or oleate 

 usually renders such rebound impossible, but this effect appears to 

 depend upon undissolved greasy matter. At least the drops from a 

 nearly vertical fountain of clear solution of soap were found not to 

 scatter.* The rebound of jets is, however, a far more delicate test 

 than that of drops. A fountain of strong saponine differs in appear- 

 ance from one of water; but this effect is due rather to the super- 

 ficial viscosity, which retards, or altogether prevents, the resolution 

 into drops. 



The failure of rebound when jets or drops containing milk or un- 

 dissolved soap come into collision has not been fully explained ; but 

 it is probably connected with the disturbance which must arise when 

 a particle of grease from the interior reaches the surface of one of the 

 liquid masses. 



P.S. — I have lately found that the high tension of recently formed 

 surfaces of soapy water was deduced by A. Dupre,f as long ago as 

 1869, from some experiments upon the vertical rise of fine jets. 

 Although this method is less direct than that of the present paper, 

 M. Dupre must be considered, I think, to have made out his case. It 

 is remarkable that so interesting an observation should not have 

 attracted more attention. 



III. " On the Development of the Ciliary or Motor Oculi 

 Ganglion." By J. C. Ewart, M.D. Communicated by 

 Professor M. Foster, Sec. R.S. Received February I'd, 

 1890. 



The most conflicting views have for some time been held as to the 

 origin, relations, and homology of the ciliary (motor oculi, ophthalmic, 



* 'Roy. Soc. Proc.,' June 15, 1882. 



f ' Tlieorie Mecanique de la Clialeur,' Paris, 1869. 



