PHYSIOLOGY, RECENT. 



751 



other compounds most also be present in larger 

 quantities shortly after death. If these can be 

 discovered, and their composition ascertained, 

 it may hereafter be possible to trace the source 

 of the glycogenous and saccharine bodies by a 

 process of synthesis. 



The lymphatics of the pancreas have been 

 worked out and illustrated by Dr. and Mrs. 

 Ilaggan. Sappey, of the Faculty of Medicine 

 of Paris, has published a work on the morpho- 

 logical elements of the blood, in which he de- 

 scribes the red and white corpuscles of each 

 division of the animal kingdom, and has illus- 

 trated them with many engravings. Crystal- 

 lizable forms of albumen have been obtained 

 from the seeds of the pumpkin and from hemp- 

 seed, the latter presenting the octahedrio and 

 rhombic-dodecahedrio forms that had been re- 

 garded as peculiar to hemoglobin. 



Professor Charles S. Ray, M. D., has applied 

 to the investigation of the manner of action 

 and the function of the spleen a method of indi- 

 rect observation in which he studied the rapid- 

 ity of the circulation through its blood-vessels. 

 It is fully recognized by physiologists that, 

 under normal conditions, a certain relation 

 subsists between the degree of functional ac- 

 tivity of an organ or tissue and the degree of 

 expansion of its blood-vessels. Applying this 

 rule to a series of observations on the kidney, 

 he was surprised at the closeness of the corre- 

 spondence that existed between the activity 

 with which the renal circulation was carried 

 on and the rapidity of the secretion of urine ; 

 which was so near that he found the rapidity 

 of the flow of urine could be observed indirectly 

 by watching the changes in the caliber of the 

 blood-vessels of the kidney with much greater 

 convenience than could be done directly by 

 counting the number of drops of urine which 

 escaped. It struck him that this method could 

 he most usefully applied to the investigation of 

 organs whose functions can not be studied by 

 any direct method with which wo are as yet 

 acquainted, of which the spleen is a typical 

 example ; and it is conveniently situated for 

 the purpose. His observations taught him that 

 the circulation through the spleen differs from 

 that of other organs in the important par- 

 ticular that the force which impels the blood 

 through the organ is not that of the blood- 

 pressure in the arteries, which has compara- 

 tively little influence on the volume of tho 

 spleen; but that the splenic circulation is car- 

 ried on chiefly, if not exclusively, by a rhtyh- 

 mic contraction of the muscles contained in 

 the capsule and traboculro of tho organ. Tho 

 movement is exceedingly regular, in so far as 

 rhythm is concerned, and varied but slightly 

 during hours of experiment and under consid- 

 erable changes of position. Tho process in the 

 spleen is different in nature from tho rhythmic 

 contraction and expansion which may be ob- 

 served in various organs on the " Traube- 

 Hering" blood -pressure curves showing them- 

 selves. The spleen also takes part in the pro- 



duction of these carves, but the contractions 

 they indicate are readily distinguished from 

 those which are proper to this organ and which 

 are independent of changes in the blood-press- 

 ure. Stimulation either of the contra! end of 

 a cut sensory nerve or of the medulla oblongata 

 causes a rapid contraction of the spleen. Stim- 

 ulation of the peripheral ends of both splanch- 

 nics and of both vagi causes a rapid contraction. 

 After section of these four nerves, stimulation^ 

 of a sensory nerve still causes a contraction, 

 showing that vaso-constrictor influences may 

 pass from the cerebro-spinal centers to the 

 spleen by some other route or routes than the 

 nerves named. The fact that the section of 

 these principal nerves which convey vasomotor 

 influences from the cerebro-spinal centers to 

 the spleen has so little effect on the rhythmic 

 contractions and expansions of the organ, seems 

 to indicate that the latter are regulated and 

 maintained by some mechanism contained in 

 the spleen itself. 



MM. II. Caillet de Poncy and C. Livron, 01 

 the Medical School at Marseilles, have found 

 that, when poisoning by arsenic takes place, 

 the phosphorus which exists as phosphoric acid 

 in the brain is replaced by arsenic. The sub- 

 stitution takes place in tho lecithine, a very 

 complex nitrogenized compound, which thus 

 becomes transformed into an insoluble albumi- 

 noid substance. Acute poisoning takes place 

 too rapidly for the arseniated lecithine to be 

 subjected to physiological reactions and be elim- 

 inated, and the animal dies under the local 

 influence of the poison without sensible vari- 

 ation of the normal phosphorus of the nervous 

 matter. In slow and chronic poisoning, the^. 

 replacement is less rapid; orseniated lecithine 

 is formed and acts as ordinary lecithine, pass- 

 ing gradually into the insoluble albuminoid 

 state, while the phosphorus is steadily dimin- 

 ished, giving place to the arsenic. 



Professor II. P. Bowditch and William F. 

 Southard. M. D., of the Harvard Medical School, 

 have performed a course of experiments to as- 

 certain which of the two senses, sight and 

 touch, supplies us with tho more accurate in- 

 formation as to tho position of objects arotnnl 

 us. The comparison may be made in several 

 ways, one of the most obvious of which i- to 

 compare tho smallest distances within which 

 two impressions made upon sensitive surface* 

 can be ivco^ni/e-l as -cparate and cli-tinct. It 

 has been found, for example, that the distance 

 between two luminous points, as two fixed 

 stars, must subtend a visual angle of at least 

 one minute, in order that the sources of lij-'ht 

 may be recognized as separate and distinct from 

 one another. This an^le corresponds to a dis- 

 tance of 0-00488 millimetre on the retina. The 

 smallest distance upon the surface of the body 

 at which two tactile impressions are recognized 

 as distinct is, according to Weber's researches, 

 1-1 mm. (upon the tip of the tongue). 1 1 

 it should follow that the retina is -J.'.l times 

 more accurate than the most sensitive part of 



