I02 



NATURE 



[November 29, 1S94 



lished dealing with the lighter aspects of Indian life. It 

 is pleasant to note that Herr Schmidt found the English 

 otiicials and planters everywhere very hospitable and 

 cordial, ready to assist him in his inquiries as to the 

 people, and able to give him much valuable information 

 on the subjects which he was studying. 



By Vocal Woods and Waters. Bv Edward Step. Pp. 254. 



(London : Bliss, Sands, and Foster, 1S94.) 

 A RESURRECTIO.N book, made up of papers originally 

 contributed to Good Words, Leisure Hour, Sunday 

 Magazine, Silver Link, and other periodicals. The 

 author is well known as a close observer of nature, and 

 he has the amount of poetry in his composition essential 

 in a writer on popular natural history. The book is 

 nicely printed and illustrated. 



LETTERS TO THE EDITOR. 

 [_Tke Editor dots not hold hirme!/ responsible for opinions ex- 

 tressed by his correspondents. Neither can he undertake 

 to return, or to correspond ivith the writers of, rejected 

 manuscripts intended for this or any other part cf NATURE, 

 No notice is taken 0/ anonymous communications, ] 



Acquired Characters. 



I.N reference to the question as to how far the signification 

 of the term "acquired characters" may usefully be extended 

 beyond the precise limit given in Lamarck's two laws (quoted 

 in my letter of November 15), or what phenomena may be 

 brought into close relationship with those indicated by Lamarck, 

 the following considerations, will, I think, be found useful. 



Let us consider a relatively stable local "race" of some 

 species of organism. The race is found to present a certain 

 range of variation, but has an average character ; and cases 

 approximating to the average are so far more numerous than de- 

 partures from it, that for our immediate purpose we may leave 

 the aberrant individuals out of account. The average specific 

 character is a matter which may be determined by measurement 

 and weighing. It can be stated in numerical form as to length 

 of such and such parts, breadth and depth of other parts, weight 

 {i.e. amount) of pigment or other chemical product here or 

 there. We know by experiment that these quantities can be 

 altered in immature individuals -.I'ithin limits by changing the 

 physical conditions in which the individual is placed. These 

 physical conditions are (roughly speaking) such measurable 

 quantities as those relating to temperature, light, mechanical 

 strains, moisture, and varying amounts of chemical compounds 

 or elements operating on the organism through its absorbing 

 surfaces (respiratory organs, digestive organs, integument). 



From such experiments we are led to conclude that without 

 destroying the life of an individual many characters can be in- 

 creased in quantity, bat that there is a limit beyond which they 

 cannot be so increased ; and that many characters can be re- 

 duced in quantity in the same way in an individual without 

 destroying its life, but that here also there is a limit. Hence it 

 seems that we are justified in distinguishing the "potential" 

 from the " actual " characters of an organism. 



This potentiality of the individual is something inborn or con- 

 genital. On the other hand, ihe actual quantitative condition of 

 the average characters of a naturally occurring assemblage of 

 individuals is necessarily to some extent the result of the opera- 

 tion of the measurable physical agencies which constitute the 

 normal environment of the species or race. (The range of 

 difference, it may here be noted, between the potential and the 

 actual characters of a species .-is thus indicated, is found to differ 

 very greatly in different species and in regard to different parts 

 of the organism.) Thus then every individual exhibits certain 

 quantitative characters, the amounts of which are determined by 

 the operation on the individual of given and related quantities of 

 external agencies. Toacharactcr thus quantitatively determined, 

 some writers have extended the term "acquired character," 

 inasmuch as it is not the congenital potential character in its 

 purity (if such a thing were possible) which we thus contemplate, 

 but the congenital character as moulded, increased, or restrained 

 by surrounding conditions. Hut whilst I am very decidedly of 

 opinion that a consideration of this moulding, expanding, or 

 restraining influence of the normal environment is likely to throw 



NO. 1309, VOL. 5 l] 



important light upon the implications of Lamarck's doctrine, I 

 agree most emphatically with Mr. Francis Gallon in thinking 

 that the use of the term " acquired char.icters " must be limited, 

 as indicated by Lamarck's own statement, to characters, " which 

 are regularly found in those individuals only which have been 

 suljjected to certain special and abnormal conditions" (to quote 

 Mr. Galton's words). The word "acquired " was used by 

 Lamarck, and should continue to be used as pointing to an 

 acquisition, under neiv conditions, of «<:;;■ ch.aracter or characters, 

 distinct from the normal characters which form, as it were, 

 the starting-point, however determined or brought into 

 existence. 



It is, however, true that the difference between the actual 

 characters of an individual organism as compared with its 

 potential characters — a difference the origin of which may be 

 expressed by calling the former "responsive characters" — is of 

 the same order whether the actual characters are determined in 

 their amount by the normal environment of the race, or by 

 abnormal quantitative changes of that environment. 



.\nd it seems to me, that in considering this we are led to the 

 conclusion that the second law of Lamarck is a contradiction of 

 the first. Normal conditions of environment have for many 

 thousands of generations moulded the individuals of a given 

 species of organism, and determined as each individual developed 

 and grew "responsive" quantities in its p.irts (characters) ; yet, 

 as Lamarck tells us, and as we know, there is in every indi- 

 vidual born a potentiality which has not been extinguished. 

 Change the normal conditions of the species in the case of a 

 young individual taken to-day from the site where for thousands 

 of generations its ancestors have responded in a perfectly defined 

 wav to the normal and defined conditions of environment ; 

 reduce the daily or the seasonal amount of solar r.idiation to 

 which the individual is exposed ; or remove the aqueous vapour 

 from the atmosphere ; or alter the chemical composition of the 

 pabulum accessible ; or force the individual to previously 

 unaccustomed muscular effort or to new pressures and strains ; 

 and (as Lamarck bids us observe), in spite of all the long-con- 

 tinued response to the earlier normal specific conditions, the 

 innate congenital potentiality shows itself The individual 

 under the new quantities of environing agencies, shows wirtw 

 responsive quantities in those parts of its structure concerned, 

 new or "acquired " characters. 



So far so good. What Lamarck next asks us to accept, as 

 his "second law," seems not only to lack the support of ex- 

 perimental proof, but to be inconsistent with what has just 

 preceded it. The new character, which is e.\: hy^olhoi, as was 

 the old character (length, breadth, weight of a part) which it 

 has replaced — a response to environment, a particular moulding 

 or manipulation by incident f )rces of the potential congenital 

 quality of the race — is, according to Lamarck, all of a sudden 

 raised to extraordinary powers. The new or freshly-acquired 

 character is declared by Lamarck and his adherents to be 

 capable of transmission by generation ; that is to say, it alters 

 the potential character of the species. It is no longer a merely 

 responsive or reactive character, determined quantitatively by 

 quantitative conditions of the envlronnR-m, but becomes fixed 

 and incorporated in the potential of the race, so as to persist 

 when other quantitative external conditions are substituted for 

 those which originally determined it. In opposition to Lamarck, 

 one must urge, in the fir>t place, that this thing has never been 

 shown experimentally to occur ; and in the second place, there 

 is no ground for holding its occjrrence to be probable, 

 but, on the contrary, strong reasun for holding it to be 

 improbable. Since the old character (length, breadth, 

 weight) had not become fixed and congenital after many 

 thousands of successive generations of individuals had developed 

 it in response to environment, but gave place to a new character 

 when new conditions operated on an individual (Lamarck's first 

 law}, why should we suppose that the new character is likely to 

 become fixed after a much shorter lime of responsive existence, 

 or to escape the operation of the first law ' Clearly there is no 

 reason (so far as Lamarck's statement goes) for any such sup- 

 position, and the two so-called laws of Lamarck are at variance 

 with one another. To push the lu.alter further — in those cases 

 in which experiment has been made, it has been found th.at a 

 character acquired by an individual removed from the operation 

 of a related condition normal to the race of which that in- 

 individual is an example, is replaced by the old character when 

 the old condition is restored in the environment of the off- 

 spring of that individual. No doubt I shall be challenged to 



