Feb. 17, 1876] 



NATURE 



;o5 



Lucina, Area, Ostrea, Purpura, Tritonium, Trochus, &c.), all of 

 which are at present living in the neighbouring sea. (2) Sam* 

 baquis, consisting almost exclusively of a small bivalve shell, the 

 "Birbigas" of the Brazilians {Venus flexuosa ?), exceedingly 

 common in shallow bays or salt-water lagoai;, the bottom of 

 which is of mixed mud and sand. (3) Sambaquis, consisting 

 exclusively of a species of Corbula, which I have not yet seen in 

 a living state ; all the Brazilians also, whom I asked, and who 

 are perfectly acquainted with any edible animal of their marine 

 fauna, are unanimous in affirming that this shell does not live 

 now on our coast. From one of these Corbula-Sambaquis I 

 obtained a specimen of a small Melampus, which I have found 

 living near the mouth of some rivulets, where fresh and salt 

 water are mingling in ever-varying proportions. When the low- 

 lands of the Lower Itajahy and some of its tributaries were as 

 yet beneath the level of the sea, they would have formed a large 

 estuary, and here probably the Corbulte lived. The fragments 

 of human skulls which we found in one of these Corbula-Sam- 

 baquis were of truly astonishing thickness, whereas those I have 

 seen from other Sambaquis are hardly thicker than our own. 

 Among the tools which are to be found in the Sambaquis, stone- 

 axes are by far the most frequent But as M. Wiener wiU pro- 

 bably soon publish a full account of his researches, I will now no 

 longer dwell on this subject. 



Some time ago I sent to Germany for publication a note on 

 the relation between our Imbauba trees (Cecropia) and the ants 

 which inhabit their hollow stem. As there may be some delay 

 in publishing, I will give you a short abstract. Mr. Belt has 

 already stated that the ants farm scale-insects in the cells of the 

 Imbauba stem, and he believes that their presence must be bene- 

 ficial. This is no doubt the case ; for they protect the young leaves 

 against the leaf-cutting ants (Oecodoma). Now there is a wonder- 

 ful contrivance by which, as in the case of the "bull's-hom acacia," 

 the attendance of the ants at the right time and place is secured. 

 At the base of each petiole there is a large flat cushion, con- 

 sisting of most densely-crowded hairs, and within this cushion a 

 large number of small white pear-like or club-shaped bodies 

 (specimens inclosed) are successively developed, which, when 

 ripe, emerge at the surface of the cushion, like asparagus on a 

 bed, and are then greedily gathered by the ants and carried 

 away to the nest. The object of the dense hair-cushion appears 

 to be (i) to secure to the young club-shaped bodies the moisture 

 necesary for their development ; and (2) to prevent the ants from 

 gathering the unripe bodies. In most cases it is by honey- 

 Kcreting glands that the protecting ants are attracted ; now 

 Mr Belt observed ("Nicaragua," p. 225) that the honey-glands 

 on the calyx and young leaves of a Passion-flower were less 

 attractive to the ants than were the scale-insects living on the 

 stems ; this would most likely be the case with the Imbauba, and 

 it is probable that the use of the little pear-shaped bodies is to 

 form an attraction stronger than that of the scale-insects, and 

 thus to secure the attendance of the protective ants on the 

 young leaves. As far as I could make out, the club-shaped 

 bodies consist mainly of an albuminous substance. The 

 a»t colonies are founded by fertilised females, which may be 

 found frequently in the cells of young Imbauba plants. Each 

 intemode has on the outside, near its upper end, a small pit 

 where the wall of the cell is much thinner than anywhere else, 

 and where the female makes a hole by which she enters. Soon 

 after this the ho?e is completely shut again by a luxuriant excres- 

 cence from its margins, and so it remains until about a dozen 

 workers have developed from the eggs of the female, when 

 the hole is opened anew from within by these workers. It 

 would appear that the female ants, living in cells closed all 

 around, must be protected against any enemy ; but notwithstand- 

 ing a rather large number of them are devoured by the grub of a 

 parasitic wasp belonging to the Chalcididse ; Mr. Westwood has 

 observed that the pupae of the Chalcididae exhibit a much nearer 



approach to the obtected pupse of the Lepidoptera than is made 

 by any other Hjrmenoptera " (" Introd. to the Modem Classif. of 

 Insects," Part XI., p. 162). Now the pupa of the parasite of the 

 Imbauba ant is suspended on the wall of the cell by its pos- 

 terior extremity just like the chrysalis of a butterfly. 



I hoi>e you will have received a paper on ^glea, a cnrions 

 Decapod inhabiting the mountain rivulets of our Serra do Mar. 

 Lately I obtained a large number of specimens of this ^Eglea, 

 and among them a female with eggs in an advanced state of 

 development. Thus I was enabled to satisfy myself that, like 

 so many fi-esh-water and terrestrial animals, the marine allies of 

 which undergo a transformation, our .lE^glea does not experience 

 any metamorphosis. Fritz Miller 



Itajahy, St. Catharina, Brazil, Dec. 25, 1875 



Prof. Tyndall on ■Germs 



Your able correspondent "Inquirer" would hardly blame 

 Horatius for taking his enemies one at a time. May I not, then, 

 claim his indulgence for following, in an extremely humble way, 

 the example of the gallant Roman ? He may accept my assu- 

 rance that during the last five months I have found Dr. Bastian 

 quite enough for me. 



Moreover, I do not think it likely that Dr. Sanderson and 

 myself will ever cross swords upon this question. Our relation, 

 I am happy to think, will be one of co-operation, not of anta- 

 gonism. The experiments on pure infusions, not those on mix- 

 tures of solids and liquids, to which "Inquirer" directs my 

 attention (Nature, voL vii., p. 180), are, in my opinion, too 

 scanty, and too little in harmony with each other, to bear an 

 inference of any weight. To Dr. Sanderson I prefer leaving the 

 repetition of then^, with the full confidence that the ability and 

 candour for which he is so distinguished will lead him to a 

 right result. 



In repeating these experiments, it would, I think, be well to 

 bear in mind the remarks of Dr. Roberts (Nature, vol. viL, 

 p. 302), however unimportant they may seem to Dr. Bastian. I 

 would also suggest the substitution, in boiling, of an oil-bath for 

 the Bunsen burner, and, in sealing, the abandonment of the 

 blow-pipe and the use of the simple spirit-lamp flame. 



Experiments on mUk and pounded cheese are, it may be ob- 

 served, at present beside the mark. They shall be subjected in 

 due time to the scrutiny already bestowed upon really liquid 

 infusions. It ought not to be forgotten that the jungle we have 

 entered has been growing umbriferously for the last six years, 

 and it is only bit by bit that the sunlight can be let in upon it. 



"Inquirer" may count on my sympathetic readiness to minister, 

 however humbly, to the delight he takes in following " every in- 

 vestigation which tends to the development of science." Il he cares 

 to see my infusions, it will give me great pleasure to show them 

 to him. Condensed abstracts only of my investigation have been 

 laid before the Royal Society and the Rojral Institution ; a fuUer 

 account of it will follow by and by. Meanwhile, I hope 

 " Inquirer " will accept the assurance that I have been strict — I 

 might say abject — in my adherence to the conditions prescribed 

 by Dr. B.istian ia his books. John Tyndall 



Heathfield, Feb, 13 



[The following letter has been sent us for publication by Prof. 

 Tyndall.— Ed.] 



Permettez-moi de vous dire combien je suis chamie que 

 vous apportiez dans la question de la generation spontanee la 

 grande autorite de votre esprit philosophique et de votre rigenr 

 experimentale. C'est tout a la fois un honneur poar mes re- 

 cherches et une vive satisfaction personelle que les conclusions 

 auxquelles vous etes arrive s'accordent si bien avec celles de 

 mes propres travaux, malgre la difference des melhodes que nous 

 avons suivies. Le tour piquant que vous avez su donner a vos 

 experiences les fera penetrcr plus avant que les miennes dans 

 I'esprit de tout lecteur que n'egarent pas les idees a priori. 



Dans le numero du 5 fevrier courant du British Medical 

 Journal le docteur Bastian accepte sans reserve I'exactitude de 

 toutes les experiences de mon memoire de 1862 {Annales de 

 Physique et de Chimie). 



II accepte egalement, sans nul doute, les resultats de celles que 

 j'ai pubhes en 1863 et en 1872 sur le sang, sur I'uriae, sur le 

 jus interieur des grains de raisin, exposes, dans I'etat meme ou 

 la vie a forme ces liquides complexes, au contact de Fair pur. 



