462 



NA TV RE 



[September b, 1894 



Bi'hr had found. He therefore concluded that the diffusion 

 hvjKjthesis was adequate to account for the interchange. Dr. 

 Haldane, replying to the above, pointed out that the criticism 

 ilii not affect those experiments of Bohr's in which the .-eroto- 

 nometer CO.. tension, although made initially higher than that 

 in the pulmonary air, yet fell in the course of an experiment to 

 a value much below the latter. 



Mr. L. Cobbett and Mr. Melsome brought before the Section 

 the results of an investigation on the production of local 

 immunity through a localised specific inflammatory condition. 

 It appeared from the authors' experiments that an attack of 

 erysipelas localised to the ear of the rabbit conferred upon that , 

 organ an immunity against subsequent inoculation by the 

 erysipelas organism so long as there was .nny indication of the i 

 inflammatory thickening occasioned by the first attack, and I 

 that the only consequence of this subsequent inoculation was a 

 localised non-specific inflammation. The authors regarded 

 this inflammation .is the reaction of the affected tissues against \ 

 the specific poison of the disease, since the absence of the specific 

 streptococci indicated that this secondary effect was not due to 

 the invasion of the tissues by the microbes. This view was 

 confirmed by the fact that it was found possible to obtain 

 similar inflammatory effects when the organisms themselves 

 having been destroyed by heat the concentrated filtered culture 

 was inj-cted into llie ear. Finally, since the parts which had 

 previously sufi^cred from erysipelas reacted more quickly and 

 vigorously to the subsequent injection of the poison, it seemed 

 probable that this non-specific inflammation was due to some 

 adaptation of the tissues enabling them to respond with greater 

 viijour, and thus more effectively, so that, as Metchnikoff and 

 others have aflirmed, the inflammatory process is from one aspect 

 a truly protective one. 



Mr. Lorrain Smith and Mr. Trevithick brought forward a 

 research in many respects similar to the foregoing, but with one 

 important difference, since the initial protective inflammatory 

 process was brought about by a simple irritant. A sterilised 

 liquid containing fine glass particles was injected into one 

 pleural cavity of the rabbit and guinea-pig. The injection was 

 followed by hyperemia of the lung and by inflammatory 

 exudation into the pleural cavity and the subjacent pulmonary 

 alveoli. The subsequent injection of the Bacillus pyocyarteus 

 was found to be inoperative as long as the injection was limited 

 to the parts which were the seat of this primary inflammatory 

 process ; thus the inflammatory region was rendered immune, 

 the localised immunity produced by the glass lasting as long as 

 twenty-eight days. 



Dr. Mann showed a series of microscopic specimens and 

 microphotographs in which changes could be observed in 

 various nerve cells as the result of iheir functional activity. 

 The cells in question were those of the spinal cord, cere- 

 bellum, &c., particularly those associated with the functional 

 activity of the retina, whilst the chief alterations were in the 

 size and chromaiin distribution of the cell nuclei. By bandaging 

 one eye of an animal and then exposing it to light, Dr. Mann 

 was able to distinguish an alteration in the size and staining of 

 the cells upon the two sides in the following siiuatinns: the 

 outer nuclear layer of the retina, the pyramidal cells of the 

 occipital cortex, and the cells of the external geniculate body. 

 The changes were most conspicuously shown both in the speci- 

 mens and in the photographs. 



.\t the meeting of the Physiological Society, held on Satur- 

 day aftcrn^>on, the following communications were made : — Dr. 

 L. IIill showed the effect of gravity in altering the mammalian 

 blood prcMure, as illustrated by the remarkable rise in carotid 

 pressure which occurs when the animal is changed from a hori- 

 zontil to a vertical position with the head down, and the corre- 

 sponding fall when the animal is similarly placeil with the head 

 up. Mr. Kent showed an organism which he believed might 

 turn out to be the specific organism of vaccinia. Dr. I'avy 

 shoA'cd a sugar of low reducing power which wa^ obtained from 

 the urine of an animal after the administration of large quanti- 

 ties of dextrose. Dr. Mott showed microphotographs of the 

 medulla, cord, &c., after section of the gracile and cuneale 

 nuclei of the monkey on one side of the medulla. The sections 

 showed the degenerated arcuate fibres sweeping over to the 

 o|)po;iic side of the medulla, and the dej;cncraiion in the fillet of 

 the opposite side above the lesion. A remarkable point in con- 

 nection with the changes was that the degenerated fibres could be 

 traced up to the optic thalamus, but no farther, there being 

 cone in the internal capsule, lie also showed microphoto- 



graphs taken from sections of a cord in which a longitudinal 

 section had been made in the lumbar region, the section being 

 in the middle line. The sections showed degenerated fibres in 

 both antero-laieral columns. 



Monday. — Dr. Starling gave an account of the experiments 

 which led him to believe that the flow of lymph from the thoracic 

 duct was dependent upon the amount of the blood-pressure in 

 the liver capillaries, and hence that the old niech.inical theory 

 of lymph formation was correct as regards this source of the 

 lymph flow. He showed that obstruction of the inferior vena 

 cava must raise the pressure in the portal capillaries, and that a 

 similar result follows obstruction of the abdominal aorla. 

 The flow of lymph which Heidenhain observed after these 

 operations was not therefore necessarily due to secretory activity, 

 but must occur in consequence of the pressure even if the per- 

 meability of the portal capillary walls remained unaltered. 

 Similarly the injection of a large quantity of saline into the 

 circulation (hydrseinia^ caused an increased flow in consequence 

 of the purely mechanical rise of pressure in the liver capillaries, 

 this rise being ascertained by taking simultaneous tracings of 

 the blood pressure in the portal vein and the inferior vena cava. 

 Many lyruphagogues act bv causing hydr.-emia, and in these the 

 flow of lymph must be directly caused by the increase in the 

 portal capillary pressure. That the lymph under these circum- 

 stances conies from the liver is shown by the absence of the flow 

 from the thoracic duct when the lymphatics of the liver are 

 ligatured. Some Ivmphagogues, the action of which was 

 especially noted by Heidenhain ^such as crayfish muscle extract), 

 slimulate the flow of lymph without giving any evidence of 

 increased pressure in the portal capill.iries. The efl"ect of these 

 lymphagogues disappears after long continued ob.struciion of 

 the aorla, and on this ground, since the liver lymph still flows, 

 the author concludes ihat lymphagogues of this class act on 

 other lymph sources than the liver, and probably in the main 

 upon those present in the intestines. 



Dr. Lazarus Barlow followed with some experiments upon 

 the flow of lymph from the hind limbs. He found no increase 

 in the flow when considerable though incomplete venous ob- 

 struci ion was maintained for one hour, whilst the specific gravity of 

 the blood, muscles, and skin showed no evidence of any increase! 

 exuda'ion. Such increased flow and exudation occurred, how- 

 ever, when, after thus damming up the katabolic products, the 

 tissues under ob-ervation were supplied with blood through 

 actively dilated arterioles. The dilatation, when caused by 

 section of the sciatic nerve, led to no such increased exudation ; 

 hence he concluded that the demands of the tissue are an 

 effective factor in lymph formation. When the arteries arc 

 actively dilated, the amount of exudation varies directly as thai 

 of the venous pressure ; so that lymph formation, though not a 

 purely mechanical process, is nevertheless simpler than a pure 

 secretion, such, for instance, as exists in the salivary glands. 



Messrs. H.iyliss and .Starling communicated the results of an 

 experimental inquiry into the innervation of the portal vein. 

 The method consisted in reading the pressure in the (lorlal end 

 of the cut splenic vein, which thus formed a side branch of the 

 portal system. They found that the pressure rose when certain 

 definite anterior roots were stimul.ated, these extending in the 

 lower dorsal region from about the seventh to the tenth dorsal 

 nerves ; these, therefore, contain vaso-constrictor nerves for the 

 portal system. 



Mr. Bayliss gave a further communication upon vaso-dilator 

 nerves. He showed that the fall of blood pressure which 

 follows the excitation of the central end of the depressor nerve 

 was accompanied by vaso-dilatation, this being evidenced in 

 the case of the kidney by the simultaneous expansion of that 

 organ, and in the case of the lower limbs by their increase of 

 volume as indicated by the plethysmograph. As the vaso- 

 constrictors leave the spinal cord by the lower lumbar roots, the 

 section of the cord in the dorso-lumbar regiori will cut off the 

 vasoconstrictors, and since, under these circumstances, the 

 stimulation of the depressor still causes an increase in the 

 volume of the limb, he was led to conclude (a) that the dilat.ation 

 was really due to the increased activity of vaso-dilator centres, 

 and not lo thciliminished activity of va~o-constrictor centres ;(*) 

 that the anterior roots by which the v.a.so-dilator nerves of the 

 lower limbs leave llie cord, extend higher into the dorsal region 

 than is the case with the constrictor nerves. Corroborative ex- 

 periments were carried out in which Ihc cord was left intact, 

 whiUlthe sympathetic, in whichthevaso-dilatorsiun.wasdivided. 



Under these circumstances no increase in the volume of the 



NO. 1297, vol. 50] 



