September 



1898J 



NATURE 



485 



sodium fluoride. These are well shaken, and then transferred 

 to the gas-pump and extracted. The difference between the 

 volume of carbonic oxide found and that introduced into the 

 bulb gives the exact measure of the absorbing power of the 

 blood. The addition of the sodium fluoride (Arthus, 1892) stops 

 all consumption of oxygen, and is helped towards that end by 

 the agitation of the blood with CO. The latter produces com- 

 plete displacement of the oxygen, and thus ensures total extrac- 

 tion of the oxygen by the pump. Finally the carbonic oxide 

 fixed by the hnemoglobin can be removed by adding to the 

 residue an equal volume of saturated solution of tartaric acid. 

 This method avoids the error due to the decomposition of the 

 oxyh;^moglobin remaining incomplete, and to the consumption 

 of a certain amount of oxygen by the blood itself during 

 manipulation. By his new method De Saint-Martin arrives at 

 the result ; the power of hsemoglobin to absorb CO is very 

 variable, altering even from day to day in the same individual. 

 To estimate the respiratory power of the blood, it is necessary 

 therefore not merely to determine the quantity of haemoglobin 

 in it, but to determine the absorbing power of the haemoglobin. 

 It follows, further, that according to De Saint- Martin estimations 

 of the amount of haemoglobin in blood based upon its absorbing 

 power are quite untrustworthy. 



Dr. C. Phisalix (Paris) demonstrated the existence of an 

 oxydase in the skin of certain batrachians. The skin of the frog 

 is macerated in saline, and the juice thus obtained is placed in 

 three tubes. The first is heated to boiling, the second is sealed 

 in vacuo, the third is left open to the air. The first and second 

 preserve their original tint, the third turns brown, the brown 

 colour commencing at and spreading from the surface of the 

 fluid. At the end of five days the whole fluid is a deep brown. 

 The fresh juice turns tincture of guiacum blue. 



I'rof. Moussu (Alfort) communicated a paper upon the 

 functions of the thyroid and parathyroid bodies. Extract of 

 parathyroid has no alleviative effect upon the symptoms of 

 thyroid cachexia. 



Prof. E. Schafer, F.R.S (London), gave an interesting paper 

 on the alleged sensory functions of the motor cortex cerebri. 

 The conclusion drawn by Munk is that " Schiff was right in 

 affirming that the parietal lobe is the tactile sphere as the 

 temporal is the auditory and the occipital the visual sphere." 

 Munk's view of the question has been adopted in this country 

 by Mott, who states that his experiments "support Munk's 

 conclusions that in the ' motor area ' the sensation of touch and 

 of pressure of the corresponding extremities is perceived." The 

 chief method employed by Mott for testing tactile sensibility 

 was the application of a steel spring clip to the skin (Schiff's 

 clip test). This method is completely illusory. Schafer found 

 that an animal which will apparently disregard the constant 

 pressure of even a strong clip on the skin of a paralysed limb, 

 will, nevertheless, instantly take notice of a light touch, or of a 

 light stroking with a straw upon the same limb. Experiments, 

 thirty in number, have been made. The result has been to show 

 that the assertions above quoted are entirely erroneous : that, in 

 fact, complete voluntary motor paralysis of a part may be pro- 

 duced by a cortical lesion without perceptible loss of tactile 

 sensibility. It cannot, therefore, be the case that the motor 

 paralysis which is produced by a lesion of the Rolandic area is 

 due to a sensory disturbance. And it also follows that tactile 

 sensibility is not localised in the same part of the cortex from 

 which voluntary motor impulses directly emanate. Hemian- 

 oesthesia sometimes results from an extensive lesion of the motor 

 cortex ; this is, however, not local but general, and is due to 

 the vascular and mechanical disturbance produced upon the 

 whole side of the brain by the establishment of the lesion. That 

 this is the case is shown by the fact that it is generally accom- 

 panied by hemiopia. Five experiments were made in the follow- 

 ing manner. Having exposed the upper Rolandic region in a 

 monkey, the leg-area in the gyrus marginalis is completely 

 severed by a cut passing as nearly as could be determined as far 

 down as the calloso-marginal sulcus, and at any rate deep 

 enough to sever all the fibres passing from the cortex to the 

 centrum ovale. In no case did this lesion produce anything 

 more than quite a temporary sensory disturbance, not to be 

 detected after a day or two ; and even this was exceptional. 

 The opposite leg was always completely paralysed, and gave no 

 sign of voluntary motion, although after a time "associated 

 movements " returned. The animal would at once look round 

 if the foot were touched ever so lightly with a straw, although it 

 would usually not remove a clip. After a variable period a 



NO. 1507, VOL. 58] 



second operation was performed upon the same region. In this 

 the cut was extended more deeply, so as to sever as much as 

 possible of the gyrus fornicatus ; which was in some cases re- 

 moved, in others left in situ, but with its coronal fibres cut. 

 In every case no perceptible effect was produced by this second 

 operation. The amount of actual severance of the fibres of the 

 gyrus fornicatus varied, but in two it was considerable ; and 

 since in none of these cases could any anaesthetic effect of such 

 severance be detected, it must be admitted that the result mili- 

 tates against the view that the gyrus fornicatus is the centre for 

 tactile sensibility. The result is also fatal to the view which has 

 been taken of the experiments on the gyrus fornicatus by H. 

 Munk, and accepted by Mott, that the anaesthesia found was 

 due to injury of the adjacent motor region. For in the experi- 

 ments here described, the adjacent motor region was not only 

 injured, but actually removed, without the production of any 

 anaesthesia, although the lower limb was completely paralysed. 



Dr. G. Mann (Oxford) gave a paper on higher and lower 

 centres in the mammalian cerebrum. 



Prof. A. Vitzou (Bucarest) reported recovery of sight in 

 monkeys after total ablation of the occipital lobes. The blind- 

 ness produced by the operation was only temporary, although at 

 first complete. The chief evidence that the animals see is their 

 power to avoid obstacles. The removal of the angular gyri 

 renders the blindness longer persistent. 



Drs. Moore and Reynolds (London) have examined the rate 

 of transmission of nerve-impulses through the spinal ganglia. 

 They find no appreciable delay caused by the interposed 

 nerve-cell. 



Prof. Verworn (Jena) addressed the meeting on the subject 

 of so-called hypnosis in animals. Tonic contraction of muscles 

 was, he maintained, the most characteristic symptom of the 

 condition. 



Dr. Wybauw (Brussels) found that continued perfusion of the 

 heart with normal saline destroyed the inhibitory effect of the 

 vagus. 



Prof. Boyce and Dr. Warrington (Liverpool) gave an 

 illustrated summary of the physiological structure of the brain 

 of the fowl. Certain tracts degenerate from the pallium into 

 underlying parts, namely, into the thalamencephalon and 

 mesencephalon. The anterior commissure degenerates severely 

 after removal of one hemisphere. Fibres arise from the thalamic 

 nuclei and form a commissure comparable with Gudderi's com- 

 missure. From the mesencephalon an ascending tract was 

 traced to near the junction of optic thalamus with corp. striatum, 

 and descending tracts into the ventral and lateral columns of 

 the spinal cord. In the cord itself ascending tracts can be dis- 

 tinguished traceable into cerebellum and into the upper part of 

 the cord, and descending in the ventral and lateral regions of 

 the cord. Ferrier's results on excitation of the surface of 

 hemisphere were confirmed. 



Prof, V. Frey (Zurich) communicated the results of his work 

 on the adequate stimulation of touch nerves. The intensity of 

 the just noticeable stimulus depends upon the size of tactual 

 surface ; the pressure that has to be applied per unit of surface 

 is greater the larger the continuous area of surface simultaneously 

 tested. It is not the pressure per se which determines the 

 stimulation, but the difference of pressure obtaining from point 

 to point within the skin. 



Profs. Langlois and Richet (Paris) gave an account of observ- 

 ations upon the resistance of diving animals to asphyxia. A 

 hen dies after one minute's immersion, but a duck does not 

 suffer from an immersion of even fifteen minutes. A duck with 

 occluded trachea shows asphyxia in four minutes if left in the 

 air ; if plunged in water at 20° C. it shows asphyxia only after a 

 quarter of an hour. After paralysis of the vagus by atropine, 

 plunging does not delay the asphyxia. The plunging in water 

 appears to reflexly restrain the respiratory combustions. 



Prof. Lanlaine (Toulouse) brought forward experiments which 

 show that in all cases and under all conditions the heat pro- 

 duced by an animal is equal to the heat calculated from the 

 oxygen consumed by the animal in the time of the experiment. 



Dr. R. Magnus (Heidelberg) reported an investigation upon 

 the reaction of the pupil of the isolated eel's eye under various 

 homogeneous lights. A Rowland's grating spectrum was used. 

 The two isolated eye-balls from the same eel, the pupils of 

 which under similar conditions are of similar size, were exposed 

 for twenty minutes, and then photographed by a flash-light. 

 The curve of the intensity of reaction agrees with the absorption 

 curve of the eel's rod-purple. This argues gainst an effect 



