Geological Society. 45 



let into the brass ; the scale is divided into inches, and there is one 

 inch to the left of zero, which is subdivided into tenths. The scale 

 is the work of Mr. Dollond. The paper is concluded by an account 

 of the precautions which were taken to ensure the accuracy of the 

 plane surface on which the bar rested, while the comparisons were 

 made with the microscopic apparatus described in the Philosophical 

 Transactions for 1821. The results are given in a table. 



A paper was read, entitled, "An Experimental Examination of 

 the Blood found in the Vena Portae." By James Thackeray, M.D. 

 Communicated by Sir Astley Cooper, Bart. V.P.R.S. 



The author, in the course of an inquiry into the properties of the 

 blood, was led to notice some peculiarities in the contents of the 

 vena portse, and to investigate this subject more minutely. The 

 results of the experiments which he made for this purpose are 

 chiefly the following. The blood contained in the vena portae is 

 darker than that of the other veins, inclining more to a ruddy hue 

 than to the Modena red. Being less homogeneous, it has the ap- 

 pearance of being less perfectly elaborated. Its specific gravity was 

 found to be very variable, but it is in general less than ordinary 

 venous blood. It coagulates much more quickly, and contains a 

 larger proportion of serum, but a much smaller proportion of al- 

 bumen, than blood taken from other veins. The serum obtained 

 from it is redder than common serum, in consequence of its retain- 

 ing much of the colouring matter of the blood : it has also a greater 

 specific gravity, and yields, on exsiccation, a greater weight of soHd 

 matter. On the application of heat, it concretes more quickly, but 

 much less completely, than blood from the jugular vein ; which pe- 

 culiarities are attributed by the author to the different state and 

 imperfect formation of the albumen contained in it. The crassa- 

 mentum of the blood from the vena portae does not expel its serum 

 so fully as blood from other vessels ; but it remains a soft mass, 

 unless artificial means be employed, and it yields a considerably 

 smaller quantity of fibrin. 



GEOLOGICAL SOCIETY. 



May 1 Ith, and 25th. — At the meetings held on these evenings, a 

 paper was read, entitled " A Sketcii of the principal Secondary and 

 Tertiary Formations of Germany, — by Roderick Impey Murchison, 

 Esq., Pres. G.S., F.R.S. &c." 



This communication is derived from a scries of memoranda which 

 the author has extracted from note book.s, written as he passed through 

 various parts of Germany in the last three years ; and he presents it 

 to the Geological Society in the hope, that it may rouse the atten- 

 tion of his countrymen to the increasing geological interest of that 

 country, and to the various valuable native publications which de- 

 scribe its subdivisions. He endeavours to point out, in ascending 

 order, all the German formations from the surface of the carboniferous 

 rocks up to the newest tertiary deposits, showing, as far as is possible, 

 their analogies and discrepancies when compared with those of 



England) 



