120 



NATURE 



[December 6, i 894 



cules. The fomii of aot in nests Nos. i and 2 are as follows : 

 (a\ queen (i") mile (both wiogei, bj: the queen loses ils wings 

 after marital flight), (i' large workers, {d) small workers, and 

 («) nurses. In nest No. 3 I have not yet seen the queen or 

 male, but it possesses — (j) so'.dier, {j>) larger workers, (.:) 

 smaller workers, and Kd) nurses ; but these are different in 

 foul to thise or niits No. I anl No. 2. Probably we might 

 add a third form of worker, as there are several sizes in the 

 nest. . . . 



*' It is carious that in No. I nest, from which the queen was 

 removed on August 30, new q leens and males are now being 

 developed, while in No. 2 nest, where the queen is at present, 

 nothing but workers have been brought out, and if a queen larva 

 or pupa is placed there it is at once destroyed, while worker 

 larvae or pupse are amicably received. In No. 3 all the eggs, 

 larva;, and pupae collected with the nest have been hatched, and no 

 eg^ have since made their appearance to date. There is no 

 queen with this nest. ... On November 14 I attempted to 

 prove by experiment how small a number of 'parasol' ants it 

 required to form a new colony. I placed two dozen of ants (one 

 dozen workers and one dozen nurses) In two separate nests, No. 4 

 and No. 5. With No. 4 I placed a few larva: with a few rose petals 

 for them to manipulate. With No. 5 I gave a small piece of nest 

 covered with mycelium. Oa the i6th these nests were destroyed 

 by small foraging ants, known as the ' sugar ' or ' meat ' ant, and 

 I had to remove them and replace with a new colony. My 

 notes on these are not sufficiently lengthy to be of much impor- 

 tance. Bat I no'.ed four eggs laid on the l6:h, or two days after 

 being placjd in their new quarters ; no queen being present. 

 The experiment is bein^ continued. I may mention that in 

 No. 4 nest, in which no fungus was present, the larvae of all 

 sizes appeared to change into the pupae stage at once for want 

 o( food [a fact corresponding with the fact I have named as 

 observed by myself sixty years ago in the case of wasp larv.i;]. 

 The circumstance tends to show that the development of the 

 insect is influenced entirely by the feeding it gets in the larvx 

 stage. 



" In nest No. 2 before the introduction of a queen there were 

 no eggs or larv.-t. The first worker wa> hatched on October 27, 

 or fifty-seven days afterwards, and a continual succession ha> 

 since been maintained, but as yet (November 19) no males or 

 queens have made their appearance.' 



In a lelter accompanying the report, Mr. Hart says : — 



" Since the»e were published, my notes go to prove that ants 

 -can practically manufacture at will ; male, female, soldier, 

 worker, or nurse. Same of the workers are capable of laying 

 egg^, and from these can be produced all the various forms as well 

 as from a queen's egg. 



" There does not, however, appear to be any difference in the 

 character of the food ; as I cannot find that the larger larva; are 

 fed with anything different to that given to the smaller." 



These results were obtained before the recent discussion of the 

 <]ue«tion commenced, and as they agree with the results reached 

 by Grassi in the case of the TtrmiUi,-\\ can now scarcely be 

 doubted that the various forms or classes among the social injects 

 are wholly determined by the treatment of the larvae 



S:. Leonards, December 2. IIkrbekt Spencer. 



"Acquired Characters." 



I DO not think we are in any way bound by the terms of 

 •the law enunciated by Limirck. Those laws m.iy be shown 

 to be erroneous in all but the suggestion of a principle which 

 may poisibly be developel into an important and far-reaching 

 doctrine, and if so the importance of the doctrine will be in no- 

 wise diminished by the crudity of the early .suggestion. There 

 is scarcely any scientific generalisation which does not require 

 an amended enunciation in each generation if it is to be in ac- 

 cordance with the contemporary state of knowledge. Neverthe- 

 less it seems to me that the second law of Lamarck does not 

 state thit a character acquired by individuals for Ihe first tiiiit is 

 inherited, or "alters the potential character of tile species." 

 Tne law stales tha'. nature preserves by generation what has been 

 acquired by individuals by the influence of the circumstances to 

 which their ra<c has been long exposed ; nut by the influence of 

 the circamstances lo which they alone have been exposed in their 

 own individual existences. 



leaving Lamarck's laws and doctrines entirely out of the 

 ■ juestion, if we dein; an acquired character as one which is 

 determined by the "operation on the Iniividual of given and 



NO. 1310, VOL. 51] 



related quantities of external agencies," I am not aware that 

 anyone has ever asserted that such a character is inherited. In 

 the sense of being completely reproduced in the offspring with- 

 out the operation of those external agencies. Bu; I think there 

 Is reason to believe that if the same quantity of external agency 

 acts on successive generations, it will produce more effect on 

 the second than on the first, or, to use more correct language, 

 that the effect in the second generation will be increased by a 

 potentiality derived from the dxA. It is argued that the very 

 possibility of the acquisition of new characters by the individnal 

 under new conditions is a proof that the old character had not 

 become fixed and congenital after the action of the old condition 

 on thousands of successive generations. But this is an illus- 

 tration of the difficulty of completely expressing the problem 

 in abstract language without reference to particular cases. If 

 I we consider the case of the pigmentation of the skin of the 

 I flounder, we find experimentally that exposure to light of the 

 1 lower side for some years produces some pigmentation, but not 

 so much as that on the upper side exposed in the individual for 

 I the same time. The action on the two sides in the individual 

 being thus equal, or even greater on the lower side, how are we 

 lo account for the difference in favour of the upper? Evidently 

 the congenital potentiality of the two sides is different. The 

 old character has then become fixed and congenital to a certain 

 very important degree. If no efl'ect were produced by the 

 action of light on the lo.ver side of the individual, there would 

 be no evidence that the congenital difference in the two sides 

 had been produced by the difference in the relation to light 

 repealed in countless successive generations. O.i ihe other 

 hand. If the equal exposure of both sides produced equal pig- 

 mentation in the same time, this would be evidence that the 

 difference in the pigmentation under normal conditions was not 

 a congenital character at all. But as the facts stand, the only 

 conclusion which is in accordance with them is that the con- 

 genital difference between the two sides is due to the gradual 

 accumulation of slight effects on the congenital potentiality of 

 the germ consequent upon th; action of light in the individual, 

 I could mention many other similar instances, which I think do 

 constitute a reason for " assocLating the s imewhat superficial 

 and late responses of the parts of a growing individual to normal 

 or abnormal forces of its environment with that more subtle 

 and profound disturbance which Is permanent and affects the 

 potential char.icter of the germ." 



I am far, however, from supposing that all specific, generic, 

 or morphological characters are due to the direct action of the 

 environment in the somi, and equally far from admitting that 

 every one of these characters has a part to pl.iy in the struggle 

 for existence. J. T. Cr.NNiNt".HAM. 



Plymouth, November 30. 



The distinction between the "acquired characters" of 

 Lamarck and the other " responsive characters " which follow 

 the " influence of the normal environment " Is, I venture to 

 think, not very important. The two kinds of characters are 

 indeed admitted by Prof. Linkestcr to be "of the same order," 

 and their cssentLal unity is clearly sho.vn when we attempt to 

 trace the history of evolution as Limirck conceived it. 



'X\\t first Increase in length of the neck of the giralTe or swan 

 was no doubt, according lo Lamarck, "an acquisition under 

 ticu conditions of iic-v character." Hut when the process had 

 started, its subsequent sl.iges could hardly be spoken of in this 

 way. The effort of stretching, which was supposed to supply 

 the condition for further increase, was then neither "new " nor 

 " special and abnormal." 



In the numerous discussions of the last seven years the term 



" acquired" has b;en employed to cover both classes of charac- 



' lers, and, indeed, the argument has chiefly turned 011 the effect 



I of normal rather than abnormal and special conditions, bec.iuse 



' the evidence supplied by the former for or against hereditary 



transmission was so much more convincing than that supplied 



by the latter. 



Although the term " acquired " is an unfortunate one, and 

 has added many difficulties and obscurilies which would have 

 been avoided by the substitution of Prof. Lankesler's term, 

 " responsive, ' 1 think it would only increase the difficulties 

 if it were now authoritatively maintained that, although the 

 majority of instances discussed and the really crucial cases ad- 

 duced are "of the same order" as .acquired characters, they 

 must no longer be called by this name. 



I entirely agree with Prof. Lankestcr as to the mutual anta- 



