I 



1891.] Chemical Constitution and Physiological Action. 311 



III. "Contributions to the Study of the Connexion between 

 Chemical Constitution and Physiological Action. Part II." 

 By T. LAUDER BRUNTON, M.D., F.R.S., and J. THEODORE 

 CASH, M.D., F.R.S. Received March 2, 1891. 



(Abstract.) 



In a former paper, the authors discussed the alterations which are 

 produced in the action of ammonia by the substitution of alkyl 

 radicals for hydrogen, and by combination of the compound ammonias 

 with different acid radicals. 



In the present paper, they have examined on a similar plan the 



hysiological action of some bodies of the aromatic series. 

 The research was begun more than four years ago, a preliminary 

 mmunication having been made to this Society on March 24th, 



887. A good deal of work has been done in connexion with the 

 bject by other observers while the research was in progress. The 

 suits obtained by others, however, are not easy of comparison, 

 hile the experiments of the authors, having been made as nearly as 

 ,sible under the same conditions, yield results which are more 

 ily compared, so as to allow of general conclusions being drawn 

 m them. They have examined (1) the physiological action of 

 nzene, and (2) the alterations which occur in its action when one 



r more atoms of hydrogen in it are replaced by (a) haloid radicals, 



6) alcohol radicals, (c) by hydroxyl, (d) by NO 2 , and (e) by amidogen, 

 H 2 . 



They have also examined the modifications in the action of various 

 embers of the series by changes in temperature. 

 They describe the general symptoms produced by benzene and its 

 mpounds in frogs and rats, their action on muscle and nerve, on 

 'flex action, on respiration, and circulation. 



They describe a new method of registering the blood pressure and 

 se, using a slow drum for the former, and a quick one for the 



tter, so as to have the whole course of the blood pressure during an 

 periment given in a comparatively short tracing, while samples of 

 e pulse waves are taken at various periods. 



They find that the action of benzene and its compounds is chiefly 

 erted on the spinal cord, although they act also on the cerebrum 

 d, to a slight extent, on nerves and muscle. Their effect on muscle 

 d nerve is to weaken them, the paralysing action being stronger 



pon the nerve than the muscle. 



Their action on the cerebrum is evidenced by lethargy and dis- 

 clination to voluntary movement both in frogs and rats. 

 Their action on the spinal cord appears to consist in producing 

 VOL. XLIX. T 



