November 3, 19 10] 



NATURE 



27 



-ten the removal of nitrogen from the blood) and that 

 • \' rcise should be taken to increase the circulation, and 

 thus remove the nitrogen from the " slow " parts more 

 c'.iickly. 



Prof. F. S. Lee, of Columbia University, read two 

 )ers. (a) "The Cause of the Treppe." During the 

 use of the staircase the excitability of the muscle 

 leases. Clamping the trachea causes a second treppe. 

 ihlich states that the treppe is due to slowing of relaxa- 

 1, so that the increase in height of contraction is only 

 larent, as the contraction starts at a higher level ; but 

 one stage of the treppe the contractions are not pro- 

 ged, while there is no delayed relaxation during fatigue 

 mammalian muscle. {Jo) " Summation of Stimuli," 

 h Dr. M. Morse. Repeated subminimal stimuli can 

 ■ ause contraction. Traces of lactic acid, carbon dioxide, 

 and other substances that are formed during fatigue in- 

 crease the excitability of muscle. Gotschlich finds that 

 muscle becomes acid as the result of repeated subminimal 

 stimuli. Prof. Lee suggested that the treppe and summa- 

 tion of stimuli are both due to traces of fatigue substances. 

 Prof. C. S. Sherrington and Miss S. C. M. Sowton 

 presented two communications dealing with the constant 

 current as a stimulus of reflex action, and the effect of 

 the intensity of the current on the response to stimula- 

 tion. The preparation used was the isolated extens'jr 

 of the knee in decerebrate rigidity. Non-polarisable 

 electrodes were placed on an afferent nerve of the limb. 

 .A weak stimulation caused a reflex increase of tonus. 

 ' '.is is a nearer approximation to the artificial produc- 

 ! of reflex tonus than has hitherto been obtained, 

 iierwise the result of artificial stimulation is a reflex 

 : iiibition, as indeed it is with this stimulus when 

 - 'onger. .\ stronger stimulus causes an increase of tone, 

 owed by inhibition. A strong stimulus abolishes the 

 liminary increase of tone, and only inhibition results, 

 fact, the results obtained are exactly the same as 

 -e long been known for the direct stimulation of the 

 ning muscle of .'\stacus claw. Stimulation occurs at 

 make and break of the constant current, and not 

 lally during its passage. With a strength of current 

 which gives a reflex increase of tone, chloroform converts 

 the response to inhibition, and as the chloroform passes 

 off the response to the stimulus again becomes an increase 

 of tone. 



Dr. J. Tait : (i) " The Conditions Necessary for 

 Tetanus of the Heart." Refractory period of heart 

 consists of absolute and relative refractory stages. The 

 former lasts during systole, and the latter gradually 

 diminishes from the end of systole. The stronger the 

 stimulus the earlier it can be made effective in the relative 

 refractory period. If the stimuli are sufficiently strong 

 they can be effective at the end of systole, and tetanus 

 results. Very strong stimulation causes electrolysis, which 

 produces a series of contractions that gradually die away. 

 (2) " Neurogenic Origin of Normal Heart Stimulus." 

 Excised frog's heart-beat sometimes shows grouped beats 

 (Luciana groups). These are probably due to waves of 

 excitation from rhythm-producing centre. The tendency 

 to grouped beats is increased by lack of oxygen, and the 

 rate and rhythm correspond to that seen in tracings of 

 Cheyne-Stokes respiration ; hence the normal heart-beat is 

 regulated by some mechanism similar to that which is 

 affected in Cheyne-Stokes respiration. A constant 

 stimulus with waves of increasing and diminishing strength 

 would, as the strength increased, become effective earlier 

 in the relative refractorj- period, and hence the increase 

 of rate of beat. 



Dr. H. M. Vernon reported the results of some experi- 

 ments on the combination of poisons with the contrac- 

 tile substance of cardiac muscle. He used the tortoise 

 heart, and perfused it with the various solutions. 

 Alcohol, chloroform, and ether all cause effects propor- 

 tional to their concentration, and recovery occurs on re- 

 moval of the drug by fresh saline. Hydrocyanic acid and 

 sodium fluoride cause a marked effect in small concentra- 

 tions, but the action does not increase much when the 

 strength of solution is increased. Recovery is not good, 

 and is less with the stronger strengths. On removal of 

 the sodium fluoride the heart-beats show remarkable 

 oscillations of amplitude. The vitality of the heart is 



NO. 2140, VOL. 85] 



always permanently injured, as a second test with the 

 same strength causes a greater effect than at first. The 

 season and condition of the heart cause minor differences 

 in the result. 



Prof. C. S. Minot, of Harvard University, gave his 

 views on the morphology and nomenclature of blood 

 corpuscles. Present nomenclature not satisfactory. Both 

 red and white cells originate from the primitive wander- 

 ing cells (mesamoeboid). Leucocyte = white cell, and can 

 be subdivided into lymphocyte (>oung leucocyte), finely 

 granular, and coarsely granular. Erythrocyte = red cell, 

 and they can be subdivided into ichthyoid stage (cells like 

 those in fish with a nucleus showing chromatin network), 

 sauroid stage (like birds and reptiles, nucleus homo- 

 geneous, usually called normoblast), and plastid (non- 

 nucleated or mammalian type). 



Prof. C. S. Sherrington, F.R.S., Dr. E. E. Laslett, and 

 Miss F. Tozer communicated the results of some experi- 

 ments indicating the existence of afferent nerves in the 

 eye muscles. The sensory nerve-endings maintain a 

 primitive reptilian type; many "brush" and "creeper" 

 endings are found in the region where muscle and tendon 

 join. No muscle-spindles are found, but a clasping form 

 of ending, which is probably a simple form of spindle. 

 The eye muscles have a greater nerve supply than any 

 other muscles. By cutting the nerves and examining the 

 muscles after the nerves had degenerated it was proved 

 that the third, fourth, and sixth cranial nerves contain 

 sensory fibres in addition to the motor fibres, which are 

 usually stated to be the only kind present. These nerves 

 are therefore afferent-efferent nerves. No sensory fibres 

 to the extrinsic eye muscles were traceable from the first 

 division of the fifth nerve. There are a few small 

 medullated nerve-fibres which do not degenerate after 

 section of all of the foregoing nerves ; these are apparently 

 vasomotor, and come from the otic ganglion. 



Dr. Dawson Turner and Dr. T. George recorded the 

 results of the X-rays in therapeutic doses on the growing 

 brains of rabbits. The development of the exposed side 

 of the brain was slower than the other side. Fatty 

 degeneration of the irides and loss of weight occurred 

 during treatment. The subject is important, as X-rays 

 are frequently used on children in the treatment of ring- 

 worm. 



Prof. k. B. Macallum, F.R.S., read three papers : ' The 

 Origin of the Inorganic Composition of the Blood 

 Plasma," "The Inorganic Composition of the Blood 

 Plasma in the Frog after a Long Period of Inanition," 

 and " The Microchemistry of the Spermatic Elements in 

 Vertebrates." 



The first two deal with the relative amounts of the 

 inorganic salts in the blood. The ratios of these to each 

 other are fairly constant throughout, and agree with the 

 relative amounts of the same substances in sea-water ; but 

 there are some variations, and the total amounts of in- 

 organic material are different in the different species. He 

 explains the distribution of the salts as reflecting the 

 composition of the ocean at that epoch when the blood 

 plasma of the species in question ceased to respond to 

 changes in the salts of the ocean. The vertebrate kidney 

 is the factor that maintains the ancestral composition of 

 the blood. 



The third paper dealt with the distribution of iron and 

 potassium in the spermatic elements. The iron in the 

 nucleus diminishes through the series spermatogonia, 

 spermatocyst, spermatid, and is absent from the head of 

 the sperm itself. Mode of elimination masked. Potassium 

 abundant in spermatic elements, gathered at anterior and 

 posterior ends in frog, and only in posterior region and 

 in bands in man. No potassium in the head itself. 



Prof. W. H. Thompson spoke on the nutritive value 

 of beef extract. Dogs were fed on a constant amount of 

 dog biscuit until their weight was steady. The addition 

 of beef extract caused an increase of weight ten or twenty 

 times as great as the amount of extract added. Boiled 

 egg-white was not nearly so efficacious. Nitrogen appar- 

 ently not retained, and when beef extract was discontinued 

 the dogs returned to their former weight. The increase 

 in weight is not due to retained water, but to an increased 

 digestion and absorption of the dog biscuits, as the 

 nitrogen and total amount of faeces were diminished. 



