270 



SCIENCE, 



[N. S. Vol. XI. No. 268. 



recent additions to the American Museum from 

 the Cope collection through the munificence of 

 President Jesup. (For a fuller account see 

 Science, N. S., XI., p. 77.) 



Bashford Dean described the condition in 

 seven eggs of Myxine glutinosa which he had 

 received from Professor A. E. Verrill. These 

 had been collected in 1880 on the Newfound- 

 laud banks in water of 90 and 150 fathoms. 

 The egg membranes were regarded as more 

 specialized than those of Bdellostoma. 



Francis E. Lloyd. 



Secretary. 



DISCUSSION AND CORRESPONDENCE. 



DO THE REACTIONS OF THE LOWER ANIMALS 

 AGAINST INJURY INDICATE PAIN SEN- 

 SATIONS ?* 



In a posthumous article with the above title 

 hy the lamented Professor Norman is contained 

 the chief substance of what was to have been 

 his doctorate thesis. It comprises new facts and 

 & statement of those that are old in a way which 

 will interest especially the psychologists and 

 gratify to no small degree the physiologists — 

 or some of them. While the author answers 

 the titular question in the negative, as his main 

 thesis, ' lower animals ' indicates for him only 

 those species up to and including the flounder. 

 Moreover, the paper is remarkably free from 

 opinions based on analogy, the evidence being 

 weighed as its author thinks solely for what it 

 is worth and regarding the particular species 

 experimented upon alone. 



The report begins with a proper adverse criti- 

 cism of that mode of argument in a circle 

 which bases presumption as to the mode of 

 consciousness concomitant to movements, on 

 these same movements taken as expressive of 

 certain modes of consciousness. He follows 

 rather the purely physiological method of con- 

 sidering movements as the immediate conse- 

 quence of physical stimulation, the psychic 

 factor not entering the problem at all. Cer- 

 tain experiments seem to the author to prove 

 the correctness of this point of view. 



* Bj the late Professor W. W. Norman, University 

 of Texas, with Additional Note by Jacques Loeb. 

 American Journal of Physiology, Vol. III., No. VI., 

 1 Jan., 1900. Pp. 270-284. 



The most striking and classic of these ex- 

 periments were made on the common earth- 

 worm (Allolobophora). If such a low animal 

 be divided at its middle transversely, only the 

 posterior half shows those squirming and jerk- 

 ing movements which, anthropomorphically 

 viewed, seem to indicate pain ; the anterior 

 half (containing the brain) crawls, as ordinarily, 

 away. Now if each of these halves be halved, 

 again the posterior segment of each squirms 

 while the anterior halves crawl away. This 

 same process may be continued with precisely 

 like result until the pieces are no longer large 

 enough to crawl independently. This striking 

 phenomenon is explained in part by the two 

 sets of muscular fibers in the worm, one longi- 

 tudinal, causing the squirming and jerking, and 

 the other circular, which produce the crawling. 

 Why in the posterior segments the former set 

 should be initially stimulated and in the an- 

 terior the latter set, Professor Norman says he 

 does not know. For its purpose the experi- 

 ment seems conclusive. Similarly, if a swim- 

 ming leech be cut in two, both parts, after a 

 pause, swim oflF as if nothing had happened. 

 Like events take place with other species of 

 worms, the anterior or brain part being regu- 

 larly that undisturbed by the extraordinary 

 stimulus. 



The abdomen of a hermit crab may be cut in 

 two without any 'but a very slight response ' 

 from any remaining movable organ. Limulus 

 stops a few seconds when four or five abdomi- 

 nal segments are cut away, then proceeds 

 quietly breathing as before. Its order of events 

 is regularly : cessation of breathing, flexion of 

 abdomen, pause, extension of abdomen, respi- 

 ratory movements. Oeophilus cut in two in 

 the middle continues its crawling, the front half 

 going forwards and the rear half backwards. 

 Millipedes divided while walking do not hasten 

 nor stop nor jerk. Dragon flies lose parts of 

 their abdomens without any appreciable change 

 in position. As was long ago pointed out, bees 

 continue to eat when their abdomens are cut 

 way during the process. 



Lastly, sharks and flounders, provided a cur- 

 rent of water circulate through their gills, will 

 allow the most tedious and deep-going cutting 

 operations on their heads without the slightest 



