July 13, 1876] 



NATURE 



237 



a peculiar kind of infection,^ by means of which the mole- 

 cular condition or force- affection of one cell is communi- 

 cated to others at a distance in the same organism. It is 

 difficult without some such hypothesis of an active mate- 

 rial exchange of living molecules between the various 

 cells of the body, to conceive of the way in which 

 " change is propagated throughout the parental system," 

 or a modified part is to " impress some corresponding 

 modification on the structures and polarities " of distant 

 units, such, for example, as those contained in the mam- 

 malian ovum. 



In the human ovary no egg-cells are produced after the 

 age of two and a half years. Each of the many hundred 

 eggs there contained reposes quietly in its follicle, whilst 

 the growth and development of other organs is proceeding. 

 Then a renewed per.od of activity for the ovary com- 

 mences, but the majority of the originally-formed egg-cells 

 retain their vitality and form-individuality for more than 

 forty years. How, we may ask, during that time are they 

 subjected to the influence of new polar forces acquired 

 by the other units of the body ? We know that they are 

 so impressed, or have such influences propagated to them. 

 Is it by " action at a distance," or by the contact action 

 of circulating infective gemmules ? 



Such being the state of speculation, in England at any 

 rate, with regard to the mechanical explanation of 

 heredity, we return to Prof. Haeckel's recently enunciated 

 theory of the Perigenesis of plastidules. 



It is clear, to begin with, that Prof. Haeckel has either 

 never studied or has forgotten Mr. Herbert Spencer's 

 writings. His attempt to substitute something better for 

 Mr. Darwin's provisional hypothesis of Pangenesis, as he 

 tells us, has its origin, to a great extent, in the admirable 

 popular lecture of Prof. Ewald Hering of Prague, " Uber 

 das Gediichtniss als eine allgemeine Function der orga- 

 nisirten Materie" [On Memory as a General Function 

 of Organised Matter], published in 1870, and to some 

 extent, including terminology, is based on an essay by 

 Elsberg, of New York, published in the Proceedings of 

 the American Association, Hartford, 1874. With the 

 latter of these publications I am only acquainted through 

 Prof. Haeckel's citations, but with the former at first 

 hand. Prof. Hering gives a brief outline in the lecture 

 in question, of the fundamental doctrine of physiological 

 psychology, which had been previously worked out to its 

 consequences on an extensive scale, by Mr. Herbert 

 Spencer. Prof. Hering has the merit of introducing 

 some striking phraseology into his treatment of the sub- 

 ject, which serves to emphasise the leading idea. He 

 points out that since all transmission of " qualities " from 

 cell to cell in the growth and repair of one and the same 

 organ, or from parent to offspring, is a transmission of 

 vibrations or affections of material particles, whether 

 these qualities manifest themselves as form, or as a 

 facility for entering upon a given series of vibrations, 

 we may speak of all such phenomena as " memory," 

 whether it be the conscious memory exhibited by the 

 nerve-cells of the brain or the unconscious memory we 

 call habit, or the inherited memory we call instinct ; or 

 whether again it be the reproduction of parental form 

 and minute structure. All equally may be called " the 

 memory of living matter," From the earliest existence of 

 protoplasm to the present day, the memory of living 

 matter is continuous. Though individuals die, the uni- 

 versal memory of living matter is still carried on. 



Prof. Hering, in short, helps us to a comprehensive 

 conception of the nature of heredity and adaptation by 

 giving us the term " memory," conscious or unconscious, 

 for the continuity of Mr. Herbert Spencer's polar forces 

 or polarities of physiological units. 



^ It is a sinking exemplification of the unity of biological science that 

 we should have to look to the pathologist for the next step in this region of 

 speculation, and that fermentations, phosphorescence, fevers, and heredity, 

 should be simultaneously studied from a common point of view with 

 psychology. 



Elsberg appears (though this is only an inference on 

 my part) to be acquainted with Mr. Herbert Spencer's 

 hypothesis of physiological units. Adopting Haeckel's 

 useful term '' plastid " for a corpuscle of protoplasm (cell 

 or cytod), he designates the physiological units " plasti- 

 dules,'' a name which Haeckel has accepted, and which 

 may very possibly be found permanently useful. But 

 Elsberg does not appear to have helped on the discussion 

 of the subject to a great extent, since he proceeds no 

 further than is implied in adopting Mr. Darwin's theory 

 of Pangenesis, whilst substituting the " plastidules " for 

 Mr. Darwin's " gemmules." It appears to me that Elsberg, 

 in his combination of the Spencerian and Darwinian 

 hypotheses, has omitted the sound element in the latter, 

 and retained the more questionable. He should have 

 conjoined Mr. Herbert Spencer's conception of " plasti- 

 dules " possessing special polarities or force affections 

 which they are capable of propagating as changes of state 

 {i.e., force-waves) to associated plastidules, and so to off- 

 spring with Mr. Darwin's conception of a universal and 

 continuous emission of such changes from all the cells 

 of an organism, and the frequent occurrence of a per- 

 sistently latent condition of those changes — a condition 

 which Hering's happy use of the term '' memory " enables 

 us to illustrate by the analogous (or we should rather say 

 identical) "latent" or "dormant condition" of mental 

 impressions. 



This i?, in fact, the position which Prof. Haeckel takes 

 up — though independently of what Mr. Spencer has 

 written on the suljject, excepting so far as the influence 

 of the latter is to be traced in Elsberg's essay. For 

 Haeckel, living matter, protoplasm, or plasson consists of 

 definite molecules — the plastidules — which cannot be 

 divided into smaller plastidules, but can only be split 

 into lower chemical compounds. What Mr. Spencer 

 calls polarities or polar forces Haeckel speaks of as 

 '' undulatory movements " — a symbol which has the 

 advantages and disadvantages of analogy, but which, like 

 '• polarity," is only a symbol, and covers our incapability 

 of conceiving more definitely the character of the pheno- 

 menon it designates. The undulatory movement of the 

 plastidules is the key to the mechanical explanation of all 

 the essential phenomena of life. The plastidules are 

 liable to have their undulations affected by every external 

 force, and once modified the movement does not return 

 to its pristine condition. By assimilation they continu- 

 ally increase to a certain point in size, and then divide, 

 and thus perpetuate in the undulatory movement of 

 successive generations the impressions or resultants due 

 to the action of external agencies on individual plasti- 

 dules. This is Memory. All plastidules possess memory 

 — and Memory, which we see in its ultimate analysis is 

 identical with reproduction, is the distinguishing feature 

 of the plastidule ; is that which it alone of all molecules 

 possesses in addition to the ordinary properties of the 

 physicist's molecule ; is in fact that which distinguishes it 

 as vital. To the sensitiveness of the movement of plasti- 

 dules is due Variability — to their unconscious Memory the 

 power of Hereditary Transmission. As we know them to- 

 day, they may " have learnt little and forgotten nothing " 

 in one organism, " have learnt much and forgotten much " 

 in another, but in all, their Memory, if sometimes frag- 

 mentary, yet reaches back to the dawn of life on the earth. 



E. Ray Lankester 



Addendum. — It will interest many readers to know that 

 Prof. Haeckel takes an opportunity in this pamphlet of 

 referring to Bathybius. He does not allude to the report 

 from the Challenger, to the effect that Bathybius is a 

 gelatinous precipitate of sulphate of lime, but speaks of it 

 as of old. He draws attention to the recent observations 

 of an excellent naturalist, Dr. Bessels, who, I find, in the 

 Jenaische Zeitschrift, 1875, vol. ix. p. 277, writes as 

 lollows : — " During the last American expedition to the 

 North Pole, I found, at a depth of ninety-two fathoms in 



