332 



NATURE 



[May 12, 192 1 



graduation than similar pre-war German articles. 

 The British firms manufacturing scientific glassware 

 are controlled by trained men of science who have 

 had long practical experience in the use of the articles 

 produced and appreciate fully the essential features 

 of particular pieces of apparatus. 



Manufacturers are desirous of meeting the require- 

 ments of consumers so far as possible, and if users 

 of chemical apparatus would acquaint manufacturers 

 directly with their special requirements and difficulties 

 or offer practical suggestions for improvement, further 

 advances might soon be made. 



The advances that have already been made can 

 be maintained and extended only if some measure of 

 security is afforded to manufacturers. Up to date 

 the industry has been largely in the experimental 

 stage, and manufacturing costs have consequently 

 been high. Manufacturers are faced with competition 

 by imported glassware which is frequently sold under 

 cost price in order to regain the British market. This, 

 together with the present rates of exchange, de- 

 prives fhem of any incentive to put down fresh plant 

 or to design new furnaces specially adapted to the 

 manufacture of scientific glassware, which would 

 render the products at the same time cheaper and of 

 better quality. 



The British manufacturer should have an oppor- 

 tunity in reasonable security to develop under normal 

 conditions the industry he established with such 

 success in the stress and strain of the war period. 

 Should there ever be another war it is certain that 

 the extension of "chemical warfare " would be on a 

 scale far greater than anything experienced in the 

 late war, and the position of this country^ would 

 indeed be hopeless if it -were dependent on imports 

 for supplies of essential scientific and laboratory glass- 

 ware. There would not again be an opportunity given 

 for the industry to be re-created In time to be efificient. 

 J. H. Davidson. 

 (Messrs. Wood Bros. Glass Co., Ltd.) 



Barnsley, April 13. 



Protozoa and the Evolution of the Gregarious Instinct. 



In the resumd given in Nature of April 14, p. 222, 

 of the proceedings of the Academy of Sciences of Paris 

 on March 21, mention was made of the observation by 

 Mme. Anna Drzewina and G. Bohn that certain 

 aquatic animals (Convoluta and the larvae of Rana 

 fusca) become grouped together and appear to emit 

 a protective substance as a defence against toxins 

 introduced into the water. That the congregating 

 of protozoa in such circumstances had a protective 

 value of this nature was suggested by me in a note 

 to CowntrySide (August, 1913, vol. v.. No. 8, p. 541), 

 where I pointed out that the combined effort of a 

 number of organisms massed together would no doubt 

 produce a greater antitoxic effect than could a single 

 isolated organism surrounded on all sides by water 

 containing toxin. 



The grouping of protozoa can easily be observed 

 if a slide be prepared of living infusoria such as are 

 found during warm weather in flower-vases and 

 examined under the microscope, when it will be 

 found on applying a little vinegar to the edge of the 

 cover-slip that these organisms become arranged in 

 clumps or clusters, each individual being in a state 

 of vigorous vibration. As is well known, a similar 

 phenomenon occurs with bacteria under somewhat the 

 same conditions, and is made use of as a diagnostic 

 test by pathologists. Agglutination in such circum- 

 stances is usually regarded as a purely physical occur- 

 rence due to surface tension. 



NO. 2689, VOL. 107] 



It appears probable that the crowding together of 

 protozoa as a protection against toxins represents the 

 dawn of a gregarious instinct. Many modern psycho- 

 logists are in agreement that evolution of body and 

 evolution of mind are parallel; that is certainly the 

 case with the nervous system and the mind of the 

 higher vertebrates. We should, therefore, expect to 

 find in the simplest animals the beginnings of 

 mind; and purposive behaviour^the characteristic 

 of mental activity as distinct from purely psycho- 

 chemical reaction — has already been shown to 

 occur in certain protozoa by Jennings and others 

 (Jennings, "Behaviour of the Lower Organisms," 

 Columbia University Biological Series, 1906). 

 Animals the behaviour of which is purely upon 

 the instinctive plane, e.g. instincts, are provided with 

 innate dispositions tending to their own self-pre- 

 servation and to the preservation of their race. On 

 the part of protozoa, protection against toxins in 

 the water is a necessary precaution that has to be 

 taken to safeguard the individual, and therefore 

 grouping together to produce antitoxins may have 

 been an early mode of purposive behaviour in 

 the first living organisms, when toxins in the 

 water in which they lived must have been one 

 of the chief dangers besetting them in the absence 

 of larger enemies. Probably, then, we have in this 

 crowding together of protozoa the dawn of the gre- 

 garious instinct — the beginnings of that instinct seen 

 in so many different groups of the animal series and 

 terminating in its most highly evolved and complex 

 form as a fundamental element in the formation of 

 human society. Reginald James Ludford. 



Zoological Laboratory, University College, 

 London, .^pril 21. 



The Nature of Vowel Sounds. 



Prof. Scripture's arguments on this subject 

 which appeared in Nature for January 13 and 20 

 last seem to me to be open to criticism. It is 

 true, no doubt, that a strongly damped resonator 

 may be excited by periodic impulses even when its 

 free period is not an exact submultiple of the period 

 of the impulses. But it does not appear justifiable to 

 argue from this that the vibration so excited is in- 

 harmonic to the fundamental f)eriod. As an illustra- 

 tion of the error in the argument, we may consider 

 the somewhat analogous case of the vibrations of 

 the resonator of a violin. The bridge, belly, and 

 enclosed air of this instrument form a resonating 

 system having a series of free modes of vibration, 

 which, especially those of higher pitch, are strongly 

 damped by reason of the communication of energy 

 to the external atmosphere and otherwise. These free 

 periods are, in general, inharmonic to the funda- 

 mental period of the string. It is easily shown from 

 the known mode of action of the bow that the force 

 exerted by the vibrating string on the bridge changes 

 impulsively from a positive to a negative value once 

 in each period. If Prof. Scripture's argument were 

 valid, we should be entitled to argue that the response 

 of the bridge and belly to these discontinuous changes 

 of force should be inharmonic to the fundamental 

 period of the string. Actually, however, we know 

 that this Is not the case. The overtones which fall 

 near the free periods of the resonator are, no doubt, 

 strongly reinforced, but the motion of every part of 

 the violin continues to be in strictly harmonic relation 

 to the period of the forces impressed by the bow. 



So far as I can see, there Is no very vital difference 

 between the dynamical principles Involved In this and 



