1864.] 



artificially formed from Albmnen. 



351 



frequency with which we find the surfaces of serous membranes (for 

 instance, the pericardium) so often coated with fibrinous outgrowths. 



If hydrogen is passed through albumen to which a small quantity of 

 potash has been added sufficient to ensure a slight excess of alkali, 

 after the lapse of some time a dense hard horny mass will be observed, 

 especially at the point where the hydrogen comes into contact with the 

 albumen ; in fact the growth of the substance often clogs the tube to 

 such a degree that the hydrogen is prevented from further passing through 

 it. It also has a tendency to grow upon platinized platinum when placed 

 in the albuminous fluid whilst the current of hydrogen is passing. The time 

 required is, as a rule, about four days ; a temperature of 98° F. rather favours 

 its formation, but is not absolutely necessary to its production. 



The following are the chief chemical and physical reactions of the sub- 

 stance formed by hydrogen. 



It is heavier than albumen, always sinking to the bottom of the vessels. 

 It is hard, tough, semitransparent, homogeneous, and slightly elastic. It 

 swells up in cold water, and dissolves to a limited extent. The extent of its 

 solubility is less the longer the time occupied for its formation. It is more 

 soluble in hot water. Peroxide of hydrogen is not decomposed by it. 



The watery solution is not coagulated by boiling ; it is, however, pre- 

 cipitated by chlorine. Hydrochloric acid does not form a blue solution 

 with excess of that reagent. Bichloride of mercury and bichloride of plati- 

 num, after the lapse of some time, precipitate it. Tannic acid, alcohol, acetate 

 of lead, sulphate of the peroxide of iron, and alum also precipitate it from its 

 solution. It is turned yellow by nitric acid and heat. It likewise con- 

 tains a small quantity of sulphur. Chondrin behaves in a similar manner, 

 in its chemical and physical relations, to the substance thus artificially pro- 

 duced, and hence I propose to call it " artificial chondrin." 



In carrying out these experiments, I found that a very nice method of 

 obtaining a constant and equal amount of hydrogen gas was by collect- 

 ing hydrogen formed at the negative pole of a one-cell battery, and pass- 

 ing the hydrogen thus formed directly into the albumen. The amount 

 of hydrogen required was regulated by increasing or diminishing the size 

 of the negative pole. 



This form of apparatus will constantly remain a week or more in action 

 without any appreciable alteration in the quantity of hydrogen evolved. 



It may be well to describe the construction of the apparatus used. I 

 first take a common precipitating glass, and place in it a few pieces of zinc 

 with a little mercury to amalgamate it. I then take a tube about \ inch 

 in diameter, and bent in two places at a right angle ; into one end I insert a 

 platinum wire, this end I place in the glass containing the zinc ; the other 

 end 1 place in the vessel containing the albuminous fluid. Dilute sulphuric 

 acid is then added to the zinc. When contact takes place between the 

 platinum wire and the zinc, a constant stream of hydrogen is given off from 

 the platinum wire. The amount of hydrogen required can be regulated by 



