May io, 1906] 



NA TUKE 



47 



funds are forthcoming due growtti and development in tlie 

 scientific departments are impossible. There certainly 

 appears to be an absence of extravagance. The average 

 annual income of the forty-four professors is not more than 

 550/., and the average income of university teachers, other 

 than professors, is only 250/. a year. The needs of the 

 University, as detailed in the article, are indeed numerous, 

 and the means of satisfying them are at present ludicrously 

 inadequate. As has been done with wearisome iteration 

 in these columns, the article refers to American and German 

 munificence on behalf of higher education, and points out 

 the tempting chance of sensible generosity the needs of 

 C'anihridge offer to our men of wealth. The generous pro- 

 vision made for university education in Germany and the 

 L'nited States, the part played by such education in the 

 progress of a modern State, and the need that exists to 

 strengthen our intellectual defences if we are to take a 

 leading position in the struggle toward efficiency, were 

 described by Sir Norman Lockycr in his presidential address 

 to the British Association at Southport in 1903. The 

 warning uttered on that occasion, and the position taken 

 as to the significance of higher education to national pro- 

 gress, have been the means of directing attention to our 

 educational deficiencies, and a beginning has been made 

 to remedy them by increased grants to university colleges. 

 A capital sum of a million and a half sterling would solve 

 all difficulties at Cambridge, but wealthy benefactors tarry, 

 probablv because the State has not in the past shown its 

 belief in the value of university education ; meanwhile the 

 work of a great university languishes. 



SOCIETIES AND ACADEMIES. 



London. 



Royal Society, February 15. — "Reciprocal Innervation of 

 ■Antagonistic Muscles. Ninth Note. Successive Induction." 

 By Prof. C. S. Sherrington, F.R.S. 



In various reflex reactions inhibition is succeeded by 

 marked exaltation of activity in the arcs inhibited. This 

 after-effect may be figured as a rebound from inhibition. 



.\n example is the following. When a dog in which the 

 spinal cord has been transected in the thoracic region is, 

 the period of shock having passed, supported so that its 

 spine is vertical and its hind limbs hang freely, these 

 latter begin to perform a rhythmic stepping movement. 



Suppose this reflex is in regular progress and is being 

 recorded from one knee, e.g. right, by a thread passing 

 thence to a pulley and light lever, if then the other thigh 

 (left) be gently supported from behind the knee the record 

 shows that the stepping reflex at once ceases in the right 

 limb. The reflex, on recommencing after this pause, con- 

 tinues as it ceases, that is, its tempo and amplitude are 

 practically the same as before the interruption. 



This result contrasts with the following. The reflex can 

 be cut short by a strong squeeze of the tail. 



The application of this stimulus to the tail does not in 

 any way interfere mechanically with the stepping move- 

 ment. Suppose the reflex to be in regular progress and 

 recorded as before, if then the tail stimulus be applied the 

 stepping reflex is almost immediately arrested, and in both 

 limbs. The reflex remains in abeyance while the tail 

 stimulus is continued. On the cessation of the latter the 

 reflex returns, and on its return soon shows indubitable 

 increase in activity as compared with its activity before 

 the inhibitory arrest. The increase is chiefly seen in the 

 amplitude of the movement, but there is also often marke.d 

 quickening of the tempo of the rhythm. The author has 

 seen the rhythm on some occasions quickened by 30 per 

 cent. The after-increase of the reflex may persist in 

 evidence for many seconds. Its decline is gradual. 



The arrest of the stepping reflex by tail inhibition cannot 

 be prolonged indefinitely. The reflex tends to return in 

 spite of the inhibitory stimulation when the latter is long 

 persisted in. It is different when the stepping reflex is 

 arrested by lifting one knee ; the reflex does not then tend 

 to break through the arrest, however long the latter be 

 continued. In this form the arrest seems referable simply 

 to cessation of the stimulus which excites the reflex. In 

 tail inhibition the arrest seems referable to a central in- 

 hibition, the peripheral stimulus excitatory of the reflex 

 remaming in action all the time. 



NO. 1906, VOL. 74] 



The after-increase consequent upon inhibition may be 

 conveniently termed ^' st4cccssivc spinal induciioti,^^ the 

 more so as that term directs attention to the likeness 

 between the spinal process and certain visual phenomena 

 commonly designated " induction." 



Again, it is easy to evoke reflex extension of the hind 

 limb by stimulation of the skin of the opposite hind limb. 

 With the spinal dog laid on its side (e.g. left) and a thread 

 attaching the knee of the slightly fle.xed right limb to a 

 recording lever, the delivery of a stimulus at a skin-point 

 of the left foot evokes refle.x extension at right hip and 

 knee. If tiiis stimulus, at moderate and unchanged in- 

 tensity, be given at regular intervals, a series of extension 

 reflexes of regular height and duration is obtained. If in 

 the course of such a series the right limb is, during one of 

 the intervals, thrown into strong reflex flexion, the next 

 extension-reflex following on the intercurrent flexion differs 

 from those prior to it in being more ample and more pro- 

 longed. Its after-discharge is greatly increased and its 

 latency is sometimes diminished. If the test stimulus for 

 the extension-reflex be adjusted at just subliminal value, 

 the intercurrent flexion-reflex will make it supraliminal. 

 The exaltation of the extension-reflex may remain per- 

 ceptible for five minutes. 



Successive spinal induction seems to be a process 

 qualified to play a part in linking together simpler reflexes 

 so as to form from them reflex cycles of action. It 

 appears especially fitted to combine the successive opposite 

 phases of such cyclic reflexes as have been termed 

 " alternating," and shown to be particularly character- 

 istic of the locomotor activity of the mammalian spinal 

 cord. If a reflex. A, not only temporarily inhibits 

 the action of an antagonistic reflex, B, but also as an 

 immediately subsequent result induces in arc of B a phase 

 of superactivity, the central organ is in that way pre- 

 disposed for a second reflex opposite to A to occur in 

 immediate succession to A itself. Such an effect seems 

 proved by the observations in this and a preceding com- 

 munication. 



" On the Existence of Cell Communications between 

 Blastomeres." By C. Shearer. Communicated by Adam 

 Sedgwick, F.R.S. 



In cutting sections of a number of segmentation stages 

 of Eupomatus and Polygordius eggs, delicate protoplasmic 

 strands were frequently observed connecting the blasto- 

 meres. E.xperiments with different fixing reagents demon- 

 strated that they were not of the nature of coagulation 

 artifacts, or the result of disintegration of the protoplasm, 

 for in many of the sections in which they were to be seen 

 all the finer details of histological structure were well 

 preserved. Under favourable conditions they could be 

 observed during the living state, and were similar in all 

 respects to the filose strands described by Andrews in a 

 number of Metazoan eggs. They possibly afford a means 

 of coordinating the various cell activities. 



Paris. 

 Academy of Sciences, April 23. — M. H. Poincare in the 

 chair. — The president announced the accidental death of 

 M. Curie, and gave a short account of his work. — The 

 eruption of Vesuvius, and in particular, remarks on the 

 explosive phenomena : A. Lacroix. A general account of 

 the recent eruption, with particulars of the lava outflows 

 and the nature of the explosions. — .\ method allowing of 

 the study of the solar corona at other times than during 

 eclipses : G. Millochau and M. Stefanik. It is proposed 

 to photograph the regions near the sun's edge by means 

 of the spectroheliograph, isolating the line X 4303 in the 

 second slit, and eliminating the light from other radiations 

 by means of an appropriate green screen. Preliminary 

 attempts have been made at Meudon with encouraging 

 results, and the authors hope to be able to complete the 

 work at the summit of Mt. Blanc. — .\lgebraic curves of 

 constant torsion : Eugene Fabry. — Reducible groups of 

 linear and homogeneous transformations : Henry Taber. — 

 The equation of Laplace with two variables : Georges Lery. 

 — The use of an electrical tuning-fork as a generator of 

 alternating currents : M. Devaux-Charbonnel. Some 

 anomalous results obtained with the currents generated in 

 the electromagnet of an electrical tuning-fork were ex- 

 amined with a Duddell oscillograph. The effects produced 



