i8 



NA TURE 



[November 4, 1897 



sympathetic by studies carried out on Langley and Sherrington's 

 pilomotor nerve-system. Huber suggests that the nicotin 

 paralyses not the perikarya of the sympathetic neurons, but rather 

 the end baskets of the pre-ganglionic fibres. 



Prof. G. N. Stewart brought forward the results of the appli- 

 cation of a new modification of his electrical method of deter- 

 mining speed of blood flow to the question of the output of the 

 mammalian heart. The method depends upon the change of 

 resistance to the passage of electric currents through the blood 

 in an artery or vein brought about by injection of blood serum. 

 Serum conducts better than does entire blood. When the blood 

 admixed with serum reaches the point of blood vessel under exam- 

 ination, electric currents previously balanced by a Wheatstone 

 bridge are thrown out of balance, and it is arranged that a tele- 

 phone shall announce this event. A specimen of blood is drawn 

 from the corresponding artery in the other limb, and from this 

 is determined the amount of serum which must be added to the 

 normal blood to make its resistance equal to that collected 

 during the passage of the mixture. The output of the heart can, 

 from these data, be determined for the period of injection, and 

 consequently by knowing the pulse-frequency be determined for 

 a single beat. In the dog it is about 2*3 c.c. per second per 

 kilogramme of body-weight. 



Prof. Townsend Porter gave an account of observations made 

 upon a strip of the muscle of the apex of the dog's ventricle. 

 The strip is left attached only by a band of pericardium, and 

 yet exhibits in this isolated state rhythmic spontaneous beats. 

 The rhythm of its beat is slow but perfectly regular ; it is slower 

 than the rhythm of the rest of the ventricle ; it, of course, per- 

 sisted when the rest of the ventricle was arrested by excitation 

 of the vagus nerve. The blood supply was maintained 

 in the srip by means of an artery and vein in the 

 pericardium. The isolation of the strip from the rest of the 

 myocardium is found, even under microscopical examination, 

 to be absolutely complete. The contractions of the isolated 

 piece could not have been caused by excitation by the action- 

 current accompanying the systole of the rest of the ventricle, as 

 the piece was raised freely in the air. The asynchronism of the 

 beat of the isolated strip and rest of the ventricle prove the 

 same thing, also that the strip was not discharged by nerves 

 accompanying the blood vessels to the strip. Other experiments 

 showed that if an artificial circulation of diluted blood be kept 

 up through the extreme apex of the dog's heart excised and 

 hung up on cannulse the isolated apex will be vigorously, 

 coordinately, and regularly for several hours. Hence it is con- 

 cluded that the apex and other parts of the mammalian heart 

 possess spontaneous rhythmic contractility, that the cause of 

 rhythmic contraction is not a single localised coordination centre, 

 the mechanism of coordination, whatever it be, being present 

 in all parts of the ventricle. 



Prof. Porter also described experiments confirming Mac- 

 William's statement that the ventricle of the dog's heart can be 

 recovered from fibrillary contractions. The entire heart of the 

 cat can be readily made to recover even after long-continued 

 and violent fibrillary contraction by free and steady perfusion of 

 fresh blood through the coronary vessels. 



When a vein on the surface of the ventricle in situ in the 

 living animal is incised and the heart slowed by vagus excitation, 

 the flow from the cut vein is much increased during ventricular 

 contraction. The contraction of the cardiac muscle compresses 

 the veins, and to a less extent the arteries, in the substance of 

 the heart. The systole aids the circulation of blood through 

 the heart muscle. On the other hand, observations with 

 minimum manometers on the veins of the heart give no support 

 to the view that the heart acts on the coronary circulation to 

 any extent as a suction-pump, although efiiciently as a force- 

 pump. A circulation through the vessels of Thebesius was 

 demonstrated to be sufficient to keep up the rhythmic beat of 

 the right venticle after the coronary arteries have been closed. 

 Ringer's solution will not maintain the ac tivity of the mammalian 

 heart, but diluted fresh defibrinated blood will. 



Prof. Waymouth Reid gave an account of his most recent 

 researches on absorption in the intestine. Heidenhain demon- 

 strated the fact that the water, organic and inorganic solids, of 

 serum introduced into the intestine, are absorbed. The experi- 

 ment was devised in support of the theory that intestinal absorp- 

 tion is possible under conditions in which osmotic transfer is ex- 

 cluded, and it was found that even inspissated serum is absorbed. 

 Heidenhain omitted to measure the hydrostatic pressure on 

 either side of the intestinal membrane, so that the possibility of 



NO. 1462, VOL. 57] 



the result being due to filtration was not excluded ; and, indeed, 

 the ancient filtration theory of Lieberkiihn has, with the neces- 

 sary modern histological modifications, been revived of late by 

 Hamburger. In the experiments now described, the animal's 

 own serum (obtained by the centrifugal machine) was introduced 

 into a loop of its intestine, and the hydrostatic pressure in the 

 cavity of the experimental loop, and in a mesenteric vein pro- 

 ceeding from a control loop, filled with " normal saline " solu- 

 tion, observed continuously during the course of the experiment. 

 Prof. Reid now found that water, organic and inorganic solids, 

 are absorbed against considerable excess of hydrostatic pressure 

 in the blood-vessels. (Since the velocity of the blood-stream in 

 capillaries is low, it is taken for granted that the pressure in the 

 capillaries of the intestinal villi is not lower than that in a 

 mesenteric vein at the border of the gut.) The results of his 

 experiments are practically the same when all the lacteals leaving 

 the experimental loop of intestine have been occluded by ligature. 



Prof. Reid called attention to our present inability to explain 

 the phenomena. Great difficulties are offered in the face of the 

 following points, examined and proven by his experiments. 



(i) Osmosis, filtration into the blood capillaries, or into the 

 lacteals by the action of Briicke's "villus pump" are, it is 

 considered, excluded by the conditions of the experiment. 



(2) That the disappearance of the serum from the cavity of 

 the gut is simply a matter of imbibition is in the highest degree 

 improbable, because the cells must be, at the commencement 

 of the experiment, soaked to the highest degree possible in 

 those constituents of the animal's serum which they are capable 

 of taking up. 



(3) Electro-osmotic action is again improbable, because 

 secreting membranes produce ingoing electrical currents as well 

 as absorbing membranes ; and, to apply such an hypothesis, it 

 would be necessary to assume that the ingoing current of the 

 cells is active in one case (absorption), the outgoing return 

 current in the other (secretion) involving the further hypothesis of 

 some valvular nature of protoplasm with higher " porosity " in 

 the " in-out " direction in the absorbing, and the "out-in" 

 direction in the secreting, membrane. 



(4) Finally, any aspirating action of the blood current in the 

 capillaries of the villi is negligible on account of the low 

 velocity of the current in capillary districts of the circulation. 



Prof. W. H. Thompson reported on experiments continued 

 under the committee appointed to examine the effects of peptone 

 and its precursors when introduced into the circulation. The 

 experiments had dealt with the influence of pure peptone, of 

 anti-peptone, and of hetero-albumose on coagulation, on blood- 

 pressure, and on vasomotor irritability. Pure peptone was 

 found to delay but not destroy the coagulability of blood, and to 

 cause a fall in blood-pressure and to lower the vaso-muscular 

 irritability. Antipeptone was found to hasten the coagulation 

 of blood : it causes a very transient fall of arterial blood-pres- 

 sure, which is immediately followed by a long-continued slight 

 increase of blood-pressure above that present at commencement 

 of the experiment. As to deutero-albumose this substance was 

 not found to give constant results : in some experiments a marked 

 retardation, in others a marked increase of rate of coagulation of 

 blood ensued. It causes a considerable fall in the arterial 

 blood-pressure. Further experiments are in progress on the 

 subject. 



Prof. Carl Huber brought forward an important and lengthy 

 paper on the modes of ending of nerve-fibres in smooth, cardiac, 

 and striated muscles. Regarding the last-mentioned it was 

 urged that the nucleated "sole" of the motor end-plate is 

 largely an artefact, derived by expression of the interfibrillar 

 substance of the muscle-fibre The mode of ending of the 

 nerve-fibres in the muscle-spindles shows them, in agreement 

 with Sherrington's experiments, to be sensorial end-organs. 

 The methylene-blue method bears out the description of the 

 ending given by Ruffini, and reveals further details of consider- 

 able interest. 



Prof. K. Huerthle described a method by which the resist- 

 ance offered by the vascular channels of an organ to the blood- 

 flow through them may be measured The viscosity of the 

 blood which, together with the dimensions of the tubular sys- 

 tem, form the two factors on which the resistance depends, was 

 determined by allowing the blood from an artery to flow through 

 calibrated capillary tubes for thirty seconds, the quantity, 

 pressure, and duration of flow being accurately measured. The 

 internal friction of the blood of the dog is about 4*5 and of the 

 rabbit 3*2, that of water being unity. If in any particular organ 



