_, Chemistry. 263 
ing is a simple and ready method of accomplishing this end. . Grease 
the plate over by means of a rag,and a little tallow,—with a pointed 
instrument draw a line in the required direction of the cut, so as to re- 
move the grease from that spot, and penetrate slightly into the metal,— 
ass a little dilute sulphuric acid over this line by means of a feather, 
and then let a drop or two of mercury fall on the same spot,—the zine 
soon becomes amalgamated in the direction of the line, and through its 
- tire thickness ; a slight blow properly given will cause it to break. 
4 ! J.L.S. 
20. On the Presence of Carbonates in the Blood; by R. F. Marcu- 
AND, (Journ. fiir Prakt. Chem., April, 1846, and Chem. Gaz., June, 
1846, p. 213.)—In these experiments the author endeavors to substan- 
tate his former opinion upon this subject, which is in opposition to that 
of many chemists. One of the methods. by which he proceeded to 
establish the presence of carbonates in the blood was.as follows :— 
The mass obtained by evaporating five pounds of blood in a retort, 
Was conveyed into a long-necked flask, closed with a cork, through 
"Which a long funnel and a tube for conducting away the gas were in- 
Serted; the latter was fitted air tight into a Woulf’s bottle, which was 
half filled with a clear solution of barytes. On heating the liquid in 
the flask to gentle ebullition, the steam passed through the barytic solu- 
tion, causing not the slightest turbidness during the course of half an 
hour ; but on pouring dilute sulphuric acid through the funnel, and con- 
uing the gentle boiling, a white precipitate very soon appeared which 
_ Wsided in.dense flakes, and after separation from the clear liquid, dis- 
Solved €ntirely in a little hydrochloric acid, so that the precipitation 
Could not have arisen from any sulphuric acid having been carried over. 
The author repeated this experiment three times and always with the 
same result ; so he thinks himself justified in his conclusions concern- 
ing the presence of carbonates in the blood. ip Pe 8 
21. On the presence of Sulphocyanogen in Human Saliva; by Max, 
PETTENKOPER, (Buch. Rep. xli, p. 289, and Chem. Gaz., May, 1846, 
“Ds, 191.)_As authors are not agreed upon the occurrence of Sulpho- 
_ ©yanogen in the saliva, Gmelin, Ure, Liebig and Wright, speaking In 
favor of it, whilst Berzelius, Kahn and Miller are opposed Pa Me, tape 
- Peated requisite to the author to investigate the subject Again. The 
"live used was collected from the author himself, and its secretion was 
Promoted by Smoking tobacco. 
The saliva in its examination was evaporated almost to dryness, ex. 
hausted with strong spirits, again evaporated and the residue dissolved 
a i water, _ The solution was very strongly reddened by neutral chloride 
- fiton and let fall some brown flakes, but it could not be caused to dis- 
 “PPear by the addition of chloride of sodium or ammonium. The ex- 
£ 
