110 Hmts on the Subject of Animal Secretions, 



municating electricity, is proved by the well-known expe- 

 riment of taking the two hind legs of a vivacious frog, im- 

 mediately after they are cut off, laying bare the crural 

 nerves, applyins: one of these to the exposed muscles of the 

 other limb, and then when the circle is completed by rais- 

 ing the other crural nerve wiih a glass rod, and touching 

 the muscle of the limb to which it does not belong, the 

 muscles of both are excited to contractions. 



There are several circumstances in the structure of the 

 nerves, and their arrangements in animal bodies, which do 

 not appear at all apphcable to the purposes of common sen- 

 sation, and whose uses have not even been devised. Among 

 these are the plexuses in the branches of the par vagum 

 v-'hich go to the lungs, and in the nerves which go to the 

 limbs. The ganglions, which connect the nerves belong- 

 ing to the viscera with those that supply the voluntary 

 muscles, and the course of the nerves of the viscera which 

 keep up a connexion among themselves in so many diffe- 

 rent ways. 



The organs of secretion are principally made up of arte- 

 ries and veins ; but there is nothing in the different modes 

 m which these vessels ramify, that can in any way account 

 fe)r the changes in the blood, out of which the secretions 

 arise. These organs are also abundantly supplied with 

 nerves. 



With a view to determine how far any changes could be 

 produced in the blood by electricity, at all similar to se- 

 cretion, Mr. W. Brande, who has begun his career in ani- 

 mal chemistry with so much success, made the following 

 experiments, in the suggestion of which Mr. Davy afforded 

 him every assistance. 



Experiment!, Middle of January, I8O9. 



The conductors from twenty-four four-inch double plafes 

 of copper and zinc, charged with a very weak solution of 

 muriatic acid, were immersed in four ounces of blood, im- 

 mediately on its having been withdrawn from a vein in the 

 arm. The temperature of the blood was kept up at 100** 

 during the experiment. The apparatus was so constructed 

 as to admit of the products at the negative and positive 

 wires being separately collected and, examined. When the 

 electrization had been carried on for a quarter of an hour, 

 all action seemed to have ceased. The blood which had 

 • surrounded the negative wire was of a deep red colour and 

 extremely alkaline; that surrounding the positive wire was 

 slightly acid, and of a brighter hue. 



In 



