August i6, 19 17] 



NATURE 



497 



bacilli of typhoid, paratyphoid A and paratyphoid B, 

 and that for a year or more after inoculation of the 

 soldiers. Smallpox, naturally acquired, usually confers 

 a lifelong immunity. We here observe the working 

 of a law which, if recognised, has not been dealt with 

 adequately by biologists. In 1896 Wiegert, the 

 Frankfort pathologist, laid down the law.ot inertia — 

 the law that once a cell is stimulated to perform a 

 certain act, it continues to perform that act for some 

 time after the stimulus has ceased to be in operation. 

 Here is something beyond mere inertia ; the functional 

 activity once started, at least in the order of events 

 under consideration, continues too long to be com- 

 parable with physical momentum ; rather there ap- 

 pears to be the setting in motion of a cyclic process 

 of intercellular reactions and counter-reactions, the 

 one starting the other. It is preferable, therefore, to 

 employ a non-committal term, and to speak of the " law 

 of habit." Of this law numerous examples may be 

 given, both from among the bacteria and morbid 

 states in man. 



Nexti to advance further, evidence obtained from 

 medical research shows that acquirements, whether of 

 defect or excess, are capable of being passed on to the 

 next generation. There 's abundant evidence of this 

 in the case of the bacteria, and here the longer the 

 environment has acted on a given species of microbe, 

 the longer the microbe retains the impressed property, 

 but as he could not state dogmatically that there is 

 any biochemical property that is specifically fixed in 

 these lower forms, still less could he regard any 

 jy;quirement as being permaaently fixed. 



With regard to higher animals, difficulties are intro- 

 duced by intra-uterinc existence, so that the only clear 

 cases to be considered are those in which the male 

 parent alone has been subjected to the noxious or other 

 mfluence. If the lymph contains soluble toxic sub- 

 stances, it is evident that the germ cells are not pre- 

 cluded from absorbing them, and, like the other tissue 

 cells, from being influenced* by them. There are 

 many examples, clinical and experimental, of the 

 effects upon the m^ile germ cells of lead, nitrate of 

 mercury, tuberculin, abrin, etc. The most conclusive 

 "^ :vations are those of Prof. Stockard, of Cornell 

 cal College, New York, in which, by subjecting 

 iiiai- guinea-pigs for some little period to the fumes 

 of alcohol, he found not merely that the offspring 

 ttpt-f- stunted and enfeebled, but that by crossing un- 

 d offspring of alcoholised fathers, which them- 

 s had not been subjected to alcohol, the progeny 

 of the third generation showed more extreme condi- 

 tions of defect than did their parents. The import- 

 ance of these observations upon the understanding of 

 human family histories and inherited neuroses, etc., 

 was very great. 



The preceding are cases of what has been termed 

 parallel induction So long ago as 1901 the lecturer 

 pointed out how what we now term the endocrine 

 organs — the organs, that is, of internal secretion— are 

 closely associated with the generative organs, and 

 that influences from without acting upon these organs 

 by causing an excess or defect of their internal secre- 

 tions, are capable of affecting the germ cells, so that 

 there is a definite possibility that the same order of 

 disturbance which affects one or other endocrine organ 

 of the parent may present itself in the offspring. 

 Prof. E. W. MacBride has recently expressed the 

 same opinion, and there is to be seen in this possi- 

 bility or probability the solution of a long-standing 

 difficulty, namely, the admission that there is one 

 possible group of cases for which the Lamarckian 

 theory holds true, and this, oddly enough, along the 

 lines of Darwin's discarded hypothesis of pangenesis; 

 only it is not by specific corpuscular pangens, but by 

 diffused secretions that the germ cells are influenced. 

 NO. 2494, VOL. 99] 



' The Physico-Chemical Basis of Immunity and 

 Evolution. 



It had been shown that the studies upon pathc^enic 

 bacteria and upon immunity prove conclusively the 

 existence of direct adaptaticMi ot a definite order, both 

 in the lowest and in the highest forms of life. It is 

 along these lines that medical research is surely lead- 

 ing us. 



Believing that workers in medicine are in the right, 

 where is it that the other biologists have gone wrong? 

 The latter, from the morphological trend of their* 

 studies, have perforce conjured up separate individual 

 particles or structures, each the bearer of an indi- 

 vidual property or group of properties. Their concep- 

 tions have perforce been in the terms of specific 

 atomies. In his pangenesis h3pothesis Charles Dar- 

 win evolved such a conception, and in his great sanity 

 cast it aside. Weismann rioted in such, with his ids, 

 idants, and determinants, all figments of the imagina- 

 tion. The same tendency is shown and carried for- 

 ward in full vigour by the modern Mendelians. 



Suppose we start, instead, from known facts and 

 known phenomena, and upon these endeavour to build 

 up our idea of the nature of the germ cell and of the 

 organic basis of heredity. First, as to the constitu- 

 tion of living matter. \Ve know that whatever form 

 of life we investigate, animal or plant, mammoth or 

 microbe, whatever form we analyse, or whatever 

 tissue — -leaving out of account water and certain 

 vehicular salts to which no specific vital functions can 

 be attributed — just one order of highly complex com- 

 pounds is common to and to be isolated from all, and 

 these are the proteins. This universal presence in 

 itself indicates that they are intimately associated with 

 vital functions. When isolated chemically they are 

 inert ; in other words, living matter contains pro- 

 teidogenous, rather than proteid substances. Much 

 attention has to be given to the study of the chemistry 

 of the proteins in relationship to metabolism : the 

 huge size of the protein molecule, close to the limits 

 of visibility under the highest power of the microscope ; 

 its great molecular weight ; the impossibility of gain- 

 ing identical analyses of two samples of the same 

 protein, even if, like haemoglobin, crystallisable ; the 

 structure of these molecules ; their dissociation into 

 smaller complexes, the peptones ; their further dis- 

 sociation into amino-acids; the synthesis of the poly- 

 peptids. The protein molecules may, therefore, be 

 represented as a ring or chairt of linked peptone mole- 

 cules, each having its ring of glycocoll nuclei with 

 swinging side-chains. In the much simpler bodies 

 with which the organic chemist is in the main con- 

 cerned, bodies like the carbohydrates or the benzol 

 derivatives, we know how the transfer of a given 

 radicle from the alpha to the delta position, for ex- 

 ample, upon a ring may bring about a profound 

 change in the chemical and physical properties of the 

 compound. When two carbon atoms are united 

 together there are, or may be, six free affinities, and 

 when these are satisfied by six different monovalent 

 groups, twelve different isomeric arrangements are 

 possible. What must be the possibilities in a protein 

 like haemoglobin, with 700 and more carbon atoms 

 in the complex, and haemoglobin is simple compared 

 with the nucleoproteins. 



If the biophores, or molecules of living matter, be 

 at least proteidogenous, obviously it is not necessary 

 to demand a separate determinant, a separate mole- 

 cule for each specific property; it is simpler to regard 

 properties inherent in the biophores as an expression 

 of the constitution of the same, of the mode of linkage 

 of the various nuclei, their number, and the nature of 

 their side -chains. This conception is within the bounds 

 of physical possibility; Weismann 's ids and idants cer- 

 tainlv are not. 



