38 EEPOET — 18GG. 



On the Nature and Properties of Ozone and Antozone demonstrated experi- 

 mentally. By J. M. M'^Gatjley. 



On the Chemical Action of Medicines. By Dr. H. Bence Jones, F.R.S. 



The law of the conservation of energy entirely does away with every supposition 

 that medicine can create or annihilate any force. Medicines may carry latent 

 energy into each part of the body, and they may become active within by increasing 

 oxidation, nutrition, secretion, motion, and sensation ; or by their properties they 

 may put a check upon these functions by increasing the resistance or by altering 

 the conditions necessary for the conversion of latent energy into active force. 



The great fimctions of medicine are chemically to assist qualitatively or quanti- 

 tatively, first the working, and secondly, the repair of the organs and structures of 

 the body. 



For clearness, only two of the chemical actions of medicines are dwelt on in this 



paper, namely, their influence on the two processes of oxidation and of nutrition 



that continually take place in each of the textures of the body. These processes are 



aflected by medicines in at least two ways. First, directly, by the passage of the 



medicines into the different textures, where oxidation is promoted or retarded, and 



where nutrition is assisted or muscles prevented ; and secondly, indirectly, by the 



action of the medicines on the nerves that regulate the circulation, whereby the 



flow of blood through the vessels is increased or diminished. The motion equals 



F 

 the force of the heart divided by the resistance M= tt- 



On this view, the first great division of medicines consists of those which (A) 

 directly or (B) indirectly promote oxidation, or (C) directly or (D) indirectly 

 retard it. 



A. Medicines that directly promote oxidation, — Iron; oxygen and ozone; alkalies; 

 chlorine, iodine, bromine ; permanganates ?, iodates, chlorates ?, nitrates ?, strong 

 mineral, vegetable and animal irritants, as large doses of salts of antimony, cop- 

 per, zinc, mercury ; croton oil ; cantharides; all forms of motion, including heat, 

 light, and electricity. 



B. Medicines that indirectly promote oxidation by increasing the circulation. 

 Among the causes that determine the force and the frequency of the heart's con- 

 traction are, (1) the action of the nerves, (2) of the muscle, and (3) the chemical 

 and mechanical quality and quantity of the blood, and its relative proportion to 

 the system of vessels in which it is contained. 



For stimulating or checking the centre of the circulation a most highly complex 

 system of nerves exists, and a similar controlling power over the arterial capillaries 

 exists throughout the periphery. 



There are at least four different centres of nervous action for the regulation of 

 the heart. 1. A stimulating or musculomotory centre in the heart itself; 2. an 

 inhibitory centre there also ; 3. a centre which acts through the ninth pair of nerves ; 

 and 4. another with opposite action, which acts on the heart through the sympa- 

 thetic nerve. Medicines may act chemically on any or all of these centres, and 

 thereby stimulate or check the heart's action. Thus, for example, digitaline acts on 

 the centre which aflects the heart through the ninth pair, for when these nerves are 

 di^dded digitaline has no action on the heart. 



The experiments of Claude Bernard on the sublingual salivary gland show the 

 antagonistic action of the sympathetic and the chorda tj-mpani. Stimulation of 

 the sympathetic checks circidation through the gland ; whilst stimulation of the 

 chorda tympani increases the flow of blood, by which secretion and oxidation are 

 increased also. 



C. Medicines that directly retard oxidation. To this class belong all the remedies 

 which were included in the antiphlogistic regimen. Vegetable salines ; vege- 

 table acids ; mineral acids ; substances which become organic acids in the system, 

 as sugar; preparations of lead ; oxide of carbon ; sulphuretted, arseniated, anti- 

 moniated hydrogen ; oxide of nitrogen ; rest from all kinds and forms of motion, 

 mechanical, thermal, electrical, photaL 



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