Sir C. Bell on the Nervous System. 147 



where, in consequence of disease of the bodies of the vertebrae, the an- 

 terior columns of the spinal chord, and anterior roots of the nerves 

 were affected, and paralysis of the muscles to which those nerves are 

 distributed was produced, while the posterior column of the cord was 

 uninjured, and the sensibility unimpaired. The author next consi- 

 ders the respiratory system of nerves, which he regards as being 

 both muscular and sensitive, and describes as arising from a tract of 

 the spinal cord, on the outside of the corpus olivare, and anterior to 

 the processus ad cerebellum ; and which constitute columns having 

 no decussations with one another, as is the case with the other 

 systems. The conclusion he originally formed, that both the phre- 

 nic and the spinal accessory nerves are provided for motion, which 

 he had deduced from the anatomical fact of the former taking a di- 

 rect course to the diaphragm, and the latter a circuitous one for the 

 purpose of associating the muscles of the respiratory organs with 

 those which act on the chest, is, he thinks, amply confirmed by 

 subsequent experiments. He concludes his paper with some re- 

 marks on the supply of blood to the respiratory system of nerves, 

 which supply, being derived from branches of the vertebral arteries, 

 affords an explanation of several pathological phenomena. 



A paper was also read, entitled, " On the constitution of the Re- 

 sins. Part IV."* By James F. W. Johnston, Esq., M.A., F.R.S. 



This paper contains the account of the continuation of the author's 

 previous researches into the constitution of the resins, both as they 

 occur in nature, and as they appear when extracted from the natu- 

 ral products by the agency of alcohol or aether. The great difficulty 

 in this inquiry is to determine when the resin to be analysed is ob- 

 tained in its normal state ; and the author has endeavoured in each 

 case to ascertain this point by repeated analyses of the resins pre- 

 pared under different conditions. He thus arrives at the conclusion, 

 that the resin of scammony extracted from crude scammony by alco- 

 hol, and heated to 260° Fahr., is represented by C 40 H 33 Oo , con- 

 taining the largest amount of oxygen of any resin hitherto ana- 

 lysed. The resin of jalap, obtained by evaporating the alcoholic 

 extract, and afterwards boiling it in water, is represented by 

 C 40 H 34 I8 , and in the amount of oxygen it contains is only 

 surpassed by the resin of scammony. It is interesting to remark 

 that these two resins in their effects on the animal ceconomy are as 

 nearly related as these formulae show them to be in chemical consti- 

 tution. 



The resin of labdanum, extracted by alcohol from the crude 

 labdanum and evaporated, gave the formula C 4() H 33 8 ; but this 

 extract, softened in the air and water, took up from it a bitter sub- 

 stance of a brown colour. After boiling in water, the pure resin 

 is represented by C 40 H 33 7 . 



The Berengela resin, previously analysed by the author before he 

 was aware of the conditions necessary to be attended to in order to 



* [See Lond. and Edinb. Phil. Mag., vol. xv. p. 327, for the former 

 papers.] 



L2 



