December 2, 1920] 



NATURE 



449 



cerous persons contain more potassium than normal, | 

 and human cancerous material contains more radium | 

 than normal. Considerable space is devoted to the 

 various methods of treatment of cancer, which it is 

 concluded must procefni alonfj the lines of a judicious 

 combination of surgery and irradiation. 



In the Museum Journal of the University of Penn- 

 sylvania (vol. X., No. 4. December, 1919) we have an 

 . account of head-hunting among the Jivaro tribe, 

 occupying a large territory on the eastern slope of 

 the .^ndes in the Republic of Ecuador. They have 

 been called cannibals, but they never cat any part of 

 the human body. The mummified heads of their 

 enemies arc the most esteemed war trophy, because 

 the head must be present at the victory feast which 

 the hero is expected to give. The head must be pre- 

 served, because it requires many months to clear a 

 field and grow vucca and bananas to provide food for 

 the numbers attending the feast. The head is fixed 

 on a staff and paradcnl, with a tribute to the valour 

 of the slayer, before the assembled tribesmen. After 

 this an orgy of eating and drinking continues for 

 days until all the supplies are exhausted. 



The way in which one part of an organism regu- 

 lates the activity of another is a problem of supreme 

 -. interest in biology. In unicellular organisms the 

 ' transmission is local, but in multicellular organisms 

 nduction may be by the circulating fluid or by 

 ■ rves. Conduction by nerves is the main theme 

 <liscusscd bv Prof. R. S. Lillie in an address on "The 

 Nature of Protoplasmic and Nervous Transmission " 

 'Journ. Physical Chemistry, vol. xxiv., 1920, p. 165). 

 Ihe propagated disturbance in nerves cannot be a 

 I h'-mical transport because of its rapidity. A nerve- 

 impulse is always accompanied by an electrical change 

 of potential of sufficient voltage to stimulate another 

 nerve. The hypothesis is advanced that the current 

 of action stimulates a contiguous portion of nerve, 

 : thus accounting for the transmission of the impulse. 

 The negative electrical potential at an active part of 

 the nerve is short-circuited through the surrounding 

 lii'ctroiyte solution, so that the current passes in at 

 the active portion of the nerve and out at an inactive 

 part. The inactive portion of nerve is thus stimulated 

 as if by the cathode of an external stimulating 

 !icuit. The time required for the potential to reach 

 1 maximum is o<x>i of a second, and, assuming that 

 ihe current is effective over a length of 3 cm., the 

 rate of conduction would be 30 metres per second; 

 this is the value obtained for a frog's nerve at tem- 

 fvralurcs of about 15° C. The propagation of the 

 rve-imputse is compared to "passive " iron and its 

 uktivation, the two pf ' hnving much in 



common. 



The newly established French Office Scienlifique ct 

 Technique des Pfichcs maritimes is issuing a seriet 

 of Notes et Mimoircs, and No. 2, " Le Merlu," by 

 Dr. Ed. le Danois, has just been published. It is a 

 summary of our knowledge of the life-history of the 

 hake. Of late year* this has become one of the most 

 important of marine food-fishes because of its wide 

 distribution. Compared with our knowletlgc of other 

 fishes, very little is known as yet of the general 

 NO. 2666, VOL. 106] 



biology of the hake, and it has been proposed (by the 

 International Council for the Exploration of the Sea) 

 to institute investigations (to be carried out by France, 

 England, and Ireland) on this and other fishes in- 

 habiting the south-western European area. The 

 piiper under notice is therefore opportune. It is 

 almost entirely a risumi of the research which has 

 been carried out on the hake by the various fishery 

 authorities, and it is accompanied by a series of 

 sketch-charts representing the seasonal distribution of 

 the fish, the localities of fishing, the spawning places 

 and periods, and the migrations. A summary of tTie 

 European commercial hake fisheries is also given. The 

 author discusses the causes of migration, and suggests 

 a factor which seems to be new (though this is difficult 

 to sav, for no references to published work are given). 

 Food is not a factor, for that taken by the hake is 

 variable, and durmg its spawning periods (when its 

 migrations are most noticeable) it does not eat at all. 

 Its migrations cannot be correlated with any seasonal 

 changes in the plankton. On the other hand, changes 

 of temperature throughout the year either enlarge or 

 restrict its range of distribution, and variations of 

 salinity are also factors. The body of the young 

 hake is relatively dense, but as the genital organs 

 mature the density diminishes. This leads to a 

 greater energy requirement in relation to the loco- 

 motion of the fish, and it seeks water of lower salinity 

 or higher temperature, or both. Thus, by reason of 

 " the principle of least effort," the hake migrates 

 into shallower, warmer, and less saline waters as its 

 breeding season approaches. 



.\ Chadwick public lecture was delivered by Prof. 

 J. B. Farmer in the lecture hall of the Medical Society 

 of London on November 5, the subject being " Some 

 Biological .\spccts of Disease." The lecturer pointed 

 out that it was now a recognised fact that co-ordinatetl 

 growth in an organism leading to the development of 

 a particular form depended on the serial or sequential 

 nature of the reactions which went on in its cells and 

 tissues. Recognition of this was essential to a proper 

 appreciation of the larger problems of health and 

 disease. By the consideration of examples, taken 

 chiefly from the plant-world, it was shown how- 

 differences in chemical or physical environments pro- 

 duced <lefinite changes in the organism, though close 

 analysis of the facts emphasised the essential point 

 that it is only when environment was able to inter- 

 fere, as it were, with the protoplasm itself that 

 response of this kind was obtained. The effects of 

 the temporary isolation of parts of the body from the 

 material influences exerted by adjacent parts might 

 result in a permanent loosening of the ties which 

 previously hail knit the constituent cells into a 

 coherent organism, while the union of parts hitherto 

 separate sometimes led to the formation of a synthetic 

 new organism ; lichens are striking examples of this. 

 The con.scquencc8 of the mutual relations established 

 between parasite and host were dealt with, particu- 

 larly with reference to the abnormal growths which 

 can be traced to substances injected by parasitic 

 animals. Prof. Farmer then passed on to discuss 

 briefly the abnormal growths or neoplasms which 

 originate as the n-sult of obscure clianges taking 



