124 REPORT — 1855. 



mentally shown that these nuclei never can be brought in contact with each other, 

 and that all the phrenomena attendant on compression and adhesion can be explained 

 bv the atomic forces of attraction and repulsion. It was therefore the conclusion 

 of Boscovich, that the attractive and repulsive forces might have no other common 

 centre than mere mathematical points. 



It would appear, then, that we have no knowledge of any external cause of our 

 impressions on our mental force but l)y the vital and physical forces. For example, 

 we have no sensation from mere contact of objects ; we must move to feel ; we have, 

 then, sensation bv our muscular sense. We must look to see, listen to hear, sniflf 

 to smell, aud move the organs of the mouth to have the sensation of flavour. 



Matter, then, seems to have been, not without reason, considered by Turgot, 

 Prof. John Robison and Prof. Dugald Stewart as the mere cause of the pha;nomena 

 which are believed by us to be real, external and palpable objects. 



But is it possible that any such appearance can be pioduced by any combination 

 of mere forces ? 



This is no idle question of mere curiosity ; it bears on the very foundation of our 

 hopes of a future life. We have all the evidence which the present state of this 

 world can give us, that the forces by which its phtenomena are effected have always 

 existed, and are likely always to continue to exist — the immediate agents of the 

 Deity ; so immediate, indeed, as to be considered by many profound thinkers (Male- 

 branche and Norris) as evincing the presence of Deity itself, and that all our per- 

 ceptions are impressed by the conceptions of the Deity. 



It must be borne in mind that " quicquid recipitur, modo recipientis recipitur." 

 Well, therefore, might Turgot, Robison, Dugald Stewart, and all philosophers who 

 have given a candid consideration to the speculations of Berkley, say that we cannot, 

 indeed, prove or deny the existence of matter external to the mind. We are be- 

 wildered by phjeoomena for which we are at a loss to account. The author's solu- 

 tion of the difficult}^ after much consideration, is, that these phsenomena are 

 produced by impressions by physical and vital forces external to the mental force, 

 but in immediate proximity and communication with it, by the medium of the 

 union of the several branches of the fifth pair of nerves in the medulla oblongata. 



On the occurrence of Leucine and Tyrosine in the Pancreatic Fluid and 

 contents of the Intestine. By Professor Kolliker, Wtirzhurg. 



Professor Kolliker communicated the result of observations recently made by 

 Professor H. Miiller and himself on the normal occurrence of Leucine in the animal 

 organism. This nitrogenous compound, which was first obtained by decomposition 

 of various animal substances by strong chemical reagents, has been detected by Robin 

 and Verdeuil in the lungs. Afterwards Frerichs and Stjedcler found the same sub- 

 stance in diseased liver, and Virchow showed that it occurs normally in large quantity 

 in the substance of the pancreas and of the spleen ; in which latter organ it had first 

 been found by Scherer and described as Lienin. This substance was discovered by 

 the authors of the communication in the pancreatic juice of a dog, in which a fistula 

 of the pancreatic duct had been experimentally established. It was also discovered by 

 them in the contents of the duodenum and small intestine, but not in the colon, of 

 man, dogs, cats, guinea-pigs, but not in the rabbit. It maybe proper to notice that 

 the guinea-pigs employed in these observations were fed on milk. 



The leucine was obtained either by simple evaporation of the fluids, or by extrac- 

 tion by means of w^ater. It presented under the microscope a spherical form, the 

 single spheres being often marked with concentric lines, aud were found isolated or 

 aggregated in large spherical masses, or united in a laminated shape. 



Together with these corpuscles were always to be found acicular crystals forming 

 brownish spheres or dumb-bell shaped bodies, resembling those which Robin and Ver- 

 deuil have described as leucine. Stredeler and Frerichs seem to be of opinion that 

 these bodies are tyrosine. In regard to this question, the authors observe that the 

 chemical rerctions of the two kinds of corpuscles referred to are not identical, the 

 crystals not being so easily soluble in water and alcohol as the spherical bodies, but 

 they do not venture to decide whether this depends on the leucine being mixed or 

 combined with other substances. 



