1870.] Zoology. 139 



experiments are, What is the cause of the formation of peroxide of 

 silver on the positive pole, and by what means does the metallic 

 silver find its way from the positive to the negative pole ? In an 

 appendix, the author informs us that there is an error in all works 

 on physics, viz. the statement that gold (pure, of course) and 

 platinum are the only two metals which are not oxidized at the 

 positive pole, when serving as electrodes. The author finds, and 

 has confirmed by experiments carefully conducted, so as to exclude 

 any source of error, that gold itself is oxidized to a very considerable 

 extent, and that during such experiments as those alluded to, there 

 is formed a definite oxide, — Au 2 3 3H 2 ; containing gold, 79 ■ 47 

 per cent. ; oxygen, 9 ' 62 per cent. ; water, 10*91 per cent. 



A mode has been devised for depositing copper, silver, or gold 

 by the electric process upon paper or any other fibrous material. 

 This is accomplished by first rendering the paper a good conductor 

 of electricity, without coating it with any material which will peel 

 off. One of the best methods is to take a solution of nitrate of 

 silver, pour in liquid ammonia till the precipitate formed at first is 

 entirely dissolved again ; then place the paper, silk, or muslin, for 

 one or two hours in this solution. After taking it out and drying 

 well, it is exposed to a current of hydrogen gas, by which operation 

 the silver is reduced to a metallic state, and the material becomes 

 so good a conductor of electricity, that it may be electro-plated 

 with copper, silver, or gold in the usual manner. Material prepared 

 in this manner may be employed for various useful and ornamental 

 purposes. 



12. ZOOLOGY- ANIMAL PHYSIOLOGY AND 

 MOKPHOLOGY. 



Physiology. 



The Origin of the Fibrin of the Blood. — Dr. Heynsius in the 

 course of a series of investigations on the albuminoids of the blood, 

 endeavoured to determine whether any of the constituents of the 

 blood corpuscle contribute to the formation of fibrin. He finds 

 that the quantity of fibrin obtained from the same blood by the 

 same treatment is somewhat variable, owing to the defectiveness of 

 the method. By whipping the blood, a greater amount of fibrin 

 is obtained than by washing the clot. The addition of phosphate 

 of soda to the blood previous to coagulation, causes great difference 

 in the amount of fibrin. In the plasma of the dog, the quantity 

 of fibrin, or of its parent substances (as taught by Buchanan and 

 Schmidt), is certainly smaller than the quantity of fibrinogenetic 



