December 2, 1920] 



NATURE 



443 



cerebellum or the cortex) to the working of the 

 system as a whole. Both methods have yielded 

 information of great importance, but neither of 

 them gives much prospect of explaining the inti- 

 mate nature of the processes involved in nervous 

 co-ordination. The third, a field relatively barren 

 until Prof. Sherrington's work, consists in analys- 

 ing the simplest activities of the nervous system 

 by a detailed study of the reflexes. 



A "simple reflex" — i.e. the performance of an 

 isolated movement as the direct consequence of 

 sensory stimulation — is generally regarded as the 

 unit reaction of the nervous system, the behaviour 

 of the animal being compounded out of a series of 

 simple reflexes. But as this compounding of re- 

 ilexes is the chief work of the nervous system it is 

 naturally a difficult matter to isolate a single re- 

 action out of the whole behaviour of the organism ; 

 indeed, in an animal which is intact we find that 

 the response to a given stimulus may depend not 

 only on that stimulus, but also on the total effect of 

 all the sensory impulses which are entering the 

 central nervous system or have entered it previ- 

 ously. Prof. Sherrington overcame this difficulty 

 by isolating a part of the central nervous system, 

 so that relatively few sensory impulses can reach 

 it, and the reflex response to a given stimulus can 

 Ik; studied under approximately constant con- 

 ditions. His method takes advantage of the fact 

 that in the higher animals the great majority of 

 sensory impulses are those which enter the brain 

 from the sptecial sense-organs in the head. These 

 organs — the eye, ear, and nose — supply informa- 

 tion about events happening at*a distance, and it 

 is on such information that the behaviour of the 

 higher animals is largely based. For this reason 

 the brain has come to be the most important part 

 of the nervous system, and is in complete control 

 of the more primitive spinal cord, which receives 

 impulses only from sense-organs in the skin and in 

 the interior of the body. 



If the brain is cut off from the spinal cord, the 

 latter is at first completely disorganised, but in 

 a short time it recovers from the initial shock, and 



carries out simple movements of the limbs in 

 response to stimulation of the skin or of the 

 sensory nerve-fibres. These simple reflexes will 

 now occur with almost mechanical regularity, 

 because the spinal cord is isolated from the great 

 mass of continually changing impulses which 

 would otherwise reach it from the brain. In 

 practice the animal is anaesthetised and the 

 brain destroyed, usually by cutting off the 

 entire head ; as the breathing will cease, some 

 form of artificial respiration must be em- 

 ployed, but with this the decapitated carcase will 

 continue to show reflex movements for many 

 hours. Prof. Sherrington has carried out a de- 

 tailed analysis of certain of these spinal reflexes, 

 in particular the scratching movements of the 

 hind leg in response to irritation of the shoulder 

 area, the withdrawal of the foot on the application 

 of a painful stimulus, and various movements 

 which form a part of the act of walking. He 

 has studied also the " tonic " reflexes whereby 

 the animal maintains a continued posture by 

 the steady contraction of certain groups of 

 muscles. 



.\s a result of this method of research, he has 

 been able to show the chief differences between 

 conduction in the simple nerve-fibre and in the 

 more complicated pathway through the central 

 nervous system. He has shown how reflexes are 

 compounded together so that two antagonistic 

 muscles {e.g. the flexors and extensors of a limb) 

 can never be called into play at the same moment, 

 and how one reflex becomes fatigued and gives 

 place to another so that the pattern of nervous con- 

 duction is continually changing and the behaviour 

 of the animal varies even though the environment 

 remains unaltered. The general principles of re- 

 flex action which Prof. Sherrington has formulated 

 have had an immediate practical application to the 

 problems of nervous disease and experimental 

 psychology, and it is no exaggeration to say that 

 his researches have opened up an entirely new 

 chapter in the physiology of the central nervous 

 system. 



Industrial Research Associations. 



I\'. -The British Research .Association ioh the Wooi.i.en and Worsted Industries. 



Bv .\ksold Krobisher. 



'X'HE main object of the British Research 

 A .Association for the Woollen and Worsted 

 Industries is to promote ro-opcration amongst 

 wwji-using firms with the view of establishing a 

 national scheme of research into the problems 

 presented by the woollen and worsted industries. 

 In the formation of the association, and in the 

 matter of providing facilities for some work that 

 has already been done, much assistance has been 

 ifiven by educational bodies, particularly ,bv Leeds 

 I'nivcrsily and by the Bradford Technical College. 

 The scope of the work of the association includes 

 the investigation of problems arising in all 

 branches of the woollen and worsted industries — 



NO. 2666. vol.. 106] 



that is to say, the growth of wool, scouring, car- 

 lx>nising, carding, combing, spinning, weaving, 

 hosiery manufacture, dyeing, bleaching, printing, 

 finishing, and other auxiliary or related processes. 

 As certain classes of " woollen " goods also contain 

 substitute fibres, the investigation of these is also 

 necessary. 



One of the first duties of the council of the 

 association has been to make a survey of the field 

 of research which is likely to be beneficial to the 

 industry. In this connection members of the 

 association can be of great assistance in the 

 framing of a thoroughly comprehensive scheme by 

 making suggestions relating to that part of the 



