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has recently received important extensions artificially divided Infusoria were capable of through the noteworthy experiments of Nuss- subsequent spontaneous multiplication. If the baum and of Gruber, 2 who have demonstrated section is not very deep, there may arise double independently the possibility of dividing uni- monsters; but here, just as in spontaneous cellular animals so that each piece will regen- divisions, as long as there remains an organic erate the missing parts. In this manner the connecting-band, the two parts act as one innumber of individuals can be artiticially multi- dividual, showing that the nervous actions are plied. For example: Nussbaum divided a not restricted to determined paths. Gruber well-isolated Oxytricha into two equal parts, also adds, that two divided pieces may be reeither transversely or longitudinally, and found united, if they are brought together again that the edges of the cut became soon sur- quickly enough. The observation thus briefly rounded with new cilia. Although some of the announced is of such extreme interest and substance of the body, or even a nucleus, was importance, that the publication of the full delost through the operation, yet, by the follow- tails of the experiment will be eagerly awaited. ing day, the two parts converted themselves Gruber adds, that at present we cannot go into complete animals with four nuclei and nu- much beyond the proof of the existence, to a cleoli (nebenkerne) and the characteristic cili- high degree, of the regenerative capacity in ary apparatus. " The head-piece has formed unicellular organisms. He also makes the siga new hind end ; the right half, a new left half.” nificant observation, that, in the Protozoa, we The new-formed duplicate Infusoria multiplied have to do foremost with changes of function ; subsequently by spontaneous division. From in the Metazoa, with growth also. one Oxytricha cut in two, Nussbaum succeeded 2. Duplication of parts.

In these anomain raising ten normal animalcules, which sub- lies we find an organ which, although an extra sequently all encysted. After an unequal di- member, yet still conforms to the type of the vision, the parts are both still capable of species. For example : a frog is found with regeneration, but parts without a nucleus did three posterior limbs ; dissection proves the not survive ; which suggests that the formative third leg to agree anatomically with the typienergy is in some way bound up with the nu- cal organization of the frog's hind leg. In cleus. But nucleate pieces may break down. determining the importance to be attributed to Thus all attempts at artificial multiplication of this evidence, it should be remembered, on the multinucleate Opalina failed, although the the one hand, that these instances are by no division of Actinosphaerium had been success- means unusual ; on the other, that the agreefully made by Eichhorn as long ago as in the ment with the normal structure is not uniform. last century. Pelomyxa palustris has been suc- 3. Asexual reproduction. When a species cessfully divided by Greef, and Myxastrum multiplies by fission of any kind, we must asradians by Haeckel.

sume that each part, after division, possesses Gruber (l. c., p. 718) describes his experi- the formative tendency, since we see it build ments with Stentor : “ If one divides a Stentor up what is necessary to complete the typical transversely through the middle, and isolates organization of the individual. Again : a bud the two parts, one finds on the cut surface of a hydroid or polyzoon, although comprising of the hind part, after about twelve hours, a only a small part of the body, is equally encomplete peristomial field with the large cilia dowed with this uncomprehended faculty. In and buccal spiral newly formed. On the other pseudova we reach the extreme limit: in hand, the piece on which the old mouth is Aphis, for example, the parent gives off a situated has elongated itself backwards, and single cell, the capacity of which to produce attached itself in the manner peculiar to these a perfect and complicated individual, fully Infusoria. If one has made a longitudinal sec- equals the like capacity of a hydroid bud or tion, so that the peristom is cut in two, then of half a worm. the peristoms both complete themselves, and The evidence forces us to the conclusion the lateral wounds heal over.

I have repeat

that the formative force or cause is not merely edly separated by trans-section pieces consider- the original disposition of the forces and subably less than half of the original Stentor, and stances of the ovum, but that to each porthese have also regenerated themselves to com- tion of the organism is given, 1. The pattern plete animals.' Gruber, too, observed that of the whole organism; 2. The partial or com

1 M. NUSSBAUM. Ueber spontane und künstliche zelliheil. plete power to reproduce the pattern. The ung. Sitzungsb. Niederrhein. ges. pat. u. heilkunde. Bonn,

italicised formula is, of course, a very crude Dec. 15, 1884. [I regret very much that I know this paper only by Gruber's abstract.)

scientific statement, but it is the best which Ueber künstliche teilung bei Infusorien.

has occurred to me. Biolog. centralbl., iv. (No. 23) 717-7-22.

2 A. GRUBER.

The formative force, then, is a diffused ten proposed, further, to compare the cost of con

, dency. The very vagueness of the expression struction and maintenance of overhead wires serves to emphasize our ignorance concerning with the cost of construction and maintenance the real nature of the force. In this connec- of underground cables, and thus to see which tion, I venture to insist upon the fact that we is desirable from economical considerations. know little or nothing concerning any of the There are two reasons, apart from the diffifundamental properties of life, because I think culty of securing good insulation, why underthe lesson of our ignorance has not been ground lines are comparatively inefficient: learned by biologists. We encounter not in- 1. If an electric conductor be brought near frequently the assertion that life is nothing to a large mass of conducting-matter, as is a but a series of physical phenomena ; or, on the wire when it is taken down from a pole and other hand, what is less fashionable science buried in the earth, there appears in the curjust now, that life is due to a special vital rent the phenomenon of retardation, by which force. Such assertions are thoroughly unsci- each signal, instead of being sharp and disentific; most of them are entirely, the remain- tinct, is partly kept back, so that it overlaps der nearly worthless. Of what seem to me the and mingles with the next. The result is to prerequisites to be fulfilled before a general limit the speed of working of the apparatus, Theory of life is advanced, I have written else- or, if, like the telephone, it be an apparatus in where." CHARLES S. Minot. which the currents are necessarily extremely

frequent, to confuse and destroy the signals

altogether. UNDERGROUND WIRES.

2. The second difficulty is called induction, During the last few years the number of

and is noticed when two or more wires are run electric wires in all of our large cities has rap

side by side and near together, as they necesidly increased, especially since the introduc- sarily are in an underground cable. If the tion of the telephone and the electric light; signals on one wire of such a cable be sharp and the probability is that the next few years

and quick, they cause facsimile signals on all will show a further large increase. If these of the neighboring wires; and this, too, though wires run on poles, they not only disfigure the the insulation may be absolutely perfect. The streets, but seriously interfere with the opera

result of this phenomenon is, that messages tions of firemen, as we have repeatedly seen

sent over one wire are liable to be received on during the last few years.

A cobweb of wires all of the other wires; and in telephony each supported on housetops requires the line-men person can easily overhear all that the others to continually tramp through the houses and are saying over the roofs, causing annoyance to the ten

Fortunately, however, both of these difficulants, and damage to the buildings. More- ties vary with the electrical qualities of the over, wires fixed to housetops are subject to

cable ; and while I have seen cables of a thouremoval at the whim of the owner, and they

sand feet, over which it was difficult to talk, have to be continually removed from building and in which the cross-talk was nearly as loud to building as the good will of each owner is as the direct conversation, on the other hand, exhausted. Again: overhead wires, whether I have conversed easily over an underground placed on poles or housetops, are continually cable extending from Paris to Orleans, eightycoming in contact with each other, causing five miles; and this, too, while other parties annoyance and danger; and an extra heavy similarly separated were talking over other rain or sleet storm so entangles and breaks

conductors of the same cable. There was them as to entirely interrupt communication.

absolute secrecy. The annual cost of repairs of overhead wires Last summer I visited France and Germany, in cities is not less than thirty per cent of the and made, together with Mr. Berthon (chief first cost of construction.

engineer of the French telephone company), In almost all of the large cities the question Mr. Cäel (chief engineer of the French govis being asked, Why cannot those wires be ernment telegraph), and Herr Guillaume (congathered into cables and buried, along with structor of the underground lines of the German the gas and water pipes, under the streets? empire), a series of telephone experiments on In answer, it is proposed to review briefly the underground lines, varying from 5 to 100 technical difficulties that arise, and to show

miles in length, from 2.87 to 48 ohms resisthow they may be and are overcome. It is ance, and from 0.06 to 0.35 microfarads ca

pacity per mile. 1 C. 8. Minot. On the conditions to be filled by a theory of life. Proc. Amer. assoc. adv. sc., xxviii. 411.

These experiments furnish us with ample

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data from which to deduce the requisites of carry a hundred wires to the city limits, say, any cable, in order that it may transmit speech, three miles distant. Let us suppose that the and without cross-talk from the neighboring wires for the first mile rest on housetops, and conductors. These are briefly as follows: for the remainder of the distance on poles. 1. Good conductivity.

The cost will be: 2. High insulation; for without this the current leaks from one conductor to the others, 35 roof-fixtures

$1,575 80 poles, with arms, etc.

5,200 giving rise to cross-talk; and it is possible to 300 miles No. 9 wire

4,800 talk by direct leakage between two conductors Stringing 300 miles wire.

2,400 whose insulation is several million ohms.

$13,975 3. Low specific inductive capacity; for, the greater the capacity, the greater the retarda

Underground, the cost would be: tion, and the greater also the cross-talk due to induction.

6 miles (50 conductors) No. 17 lead.covered Below is a table showing the specific induc

cable

@ $3,000 $18,000

3 miles trencbing, troughing, laying, and retive capacity and insulation of various insulat- filling

@ 2,000 6,000 ors. The measurements were all made on a

$24,000 wire 0.05 of an inch in diameter, coated with insulation to a thickness of 0.10 of an inch.

That is, the relative first cost of an over

Specific head and an underground line, to do the same Cable.

work, would be, say, $14,000 and $24,000. per mile in capacity meghoms. in micro. The same conclusion will hold true for tele

phone-wires, provided we confine ourselves to Gutta-percba, Siemens Bros., London.

the problem of running out from the central India-rubber,

Ratuier, Paris.
A. G. Day, New York.

office, by fifty or a hundred conductor cables, Faraday \Faraday cable-works,

15,000 Cambridge, Mass.

to a large number of distributing-points so

situated about the city that any subscriber Chicago. David Brooks, Phila

would be easy of access, by a short overhead delphia.

line, to one or another of them; and this is

the problem that really occurs. So much for Let us take a special case, and compare a construction. gutta-percha cable having a specific inductive

The yearly cost of repairing an overhead capacity of 4.2 with a Faraday cable of 1.6.

system, including roof-rentals, is not less than The table predicts that we can talk three times

thirty per cent of the cost of construction ; as far with the latter as with the former, and

and the line would have to be renewed once in experiment shows that we can. Again: the

twelve years. The cost of repairing an undercross-talk on the gutta-percha cables ought to

ground system is practically nil. The Paris greatly exceed that on a Faraday cable; and telephone company, with wires extending to experiment has shown, that, while conversation three thousand subscribers, does not keep any over a two-mile gutta-percha cable was con

repair-men. The durability of an underground tinually disturbed by existing cross-talk, con

system, provided lead-covered cables are used, versation was carried on a similarly and there is no internal cause of deterioraconstructed Faraday cable five miles in length tion, is at least thirty years.

Last summer without the cross-talk being appreciable.

we examined some lead-incased gutta-percha By proper attention to the electrical quali

cables that had been in use by the French ties, then, we may talk underground a much

government for that length of time, and found greater distance than we shall ever have reason

them in perfectly good covdition. The same to in any city system, and this without cross- is true of India-rubber cables incased in lead. talk from the neighboring circuits.

Herr Guillaume says of a cable in use by the We have seen that telegraph and electric- German government, similar to the Faraday lighting currents are not subject to the technical

cable, “ We are using it altogether in our difficulties we have been discussing, and that, new construction. I do not see how it can ever provided good conductivity and good insulation

decay. We tried cotton-covered wires soaked are assured, it is with them purely a question of in paraffine and drawn into lead pipes; and, expense. Let us, then, determine the relative

though they worked well at first, after a few expense of overhead and underground wires.

years they failed.” Suppose we have a large city with a telegraph

W. W. JACQUES, Ph.D., office near the centre, and that it is desired to Electrician of the American Bell telephone co.

over

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48.

REDUCED FACSIMILE OF DRAWINGS SHOWING SOME EVIDENCE OF SO-CALLED THOUGHT-TRANSFERENCE.

issued a circular during the winter, describing some simple experiments in guessing digits or

persons making the trials according to the directions of the circular, and the results will

be published in the first number of the pro- natulid, so that the snail escapes notice very ceedings of the society, which will appear during readily indeed. It is abundantly found upon the summer. Besides these set experiments, the Leptogorgia, and never met with except Mr. W. H. Pickering of Boston met with some associated with it.' Last summer at Beaufort, success in the experiments which have attracted in trawling in ten fathoms of water, a few so much attention from the English society, miles off Cape Lookout, we took a Leptogorgia experiments in which a drawing thought of whose general habit was the same as that of by one person, is reproduced by another, who L. virgulata, but which was very different from has no visible means of obtaining information it in color. In this one the color is deep rose, as to what the drawing may be. In the ac- almost purple, and mottled with white at the companying illustration we have reproduced openings, where the polyps are fixed. Now, all the figures as they were drawn, numbering the question was, Is there an Ovulum for this them from 1 to 52. The upper line in each case Leptogorgia? and on examination, sure enough, contains the originals, and the lower the re- there was found a large number of the Ovuproductions. The originals were made either lums, in this case again imitating the colors of by Mr. Pickering or by one of his friends, and the host. This Ovulum is undoubtedly of the the reproductions were most of them made same species as the yellow one, for it presents by a young lady, who, on one or two evenings no difference except in color. The shell is redwhen the experiments were tried, met with brown; and the folds of skin that surround it some success. It may be well to state, that in the expanded snail are deep-rose color, and with figs. 6, 7, 8, and 20, certain extraneous mottled with white spots. Here, then, is ancauses acted which interfered with the results. other very good illustration of the familiar The first forty figures were all made in one principle that forms will vary in adaptation to day; figs. 41 to 47 inclusive were made by their surroundings, and of the part that mimanother person; the remaining figures were icry may play in natural selection. Confined made by the sensitive, so called, on a day when in aquaria, the snails sought their own corals apparently there was no thought-transference. to creep over them; and, if the red snail and

yellow coral only were put into the same aqua

rium, the snail showed not the least desire to MIMICRY AMONG MARINE MOLLUSCA.

creep over the coral, but remained creeping

about the walls of the aquarium. It is a curious fact, that, while among the I observed another snail last summer that I terrestrial animals the number of known cases feel sure must owe its shape and color, at least of protective mimicry is very large, among in part, to mimicry, though here there were not aquatic animals it is very small. I have no doubt so good grounds for the conviction as in the that the comparative poverty of ou knowl- case just mentioned. I found on the beach at edge of the habits and situation of aquatic Fort Macon, one day after a strong southerly animals in part accounts for this, but I believe gale, a single specimen of an undetermined spealso that there is really vastly less mimicking. cies of Scyllaea, a nudibranch characterized I do not know of any marine species, that, by a pair of tentacle shields, and two pairs of harmless in themselves, mimic formidable spe- elongate narrow processes of the skin upon the cies for protection ; but there are instances in back, on the inner side of which white delicate which forms are modified in color or shape so gills are placed. This creature, when placed as to resemble the surroundings in which they upon the Sargassum, or gulf-weed, shows the

live, and thus escape the observation of their closest resemblance to it. The color is almost enemies. In the summer of 1879, Dr. E. B. identical with that of the alga, a light brown. Wilson, while studying in Brooks's laboratory The body is elongate and much compressed, at Beaufort, N.C., found abundant specimens and the foot-sole an elongate, narrow groove, of Ovulum uniplicatum, - a mollusk living perfectly adapted for adhering to the alga stem. upon the stems of Leptogorgia virgulata (a The tentacle sheaths and the skin processes sea-fan abundant there in shallow sounds). upon the back are thin, and at the edges are The stem of the sea-fan is of an orange-yellow wavy, and present the most perfect resemcolor, and, further, is often marked with yellow blance to the leaves (?) of the alga. The swellings where the coral has spread itself over compressed body is further terminated postethe shell of an attached barnacle. The Ovulum riorly by a thin vertical portion like a fin, has a yellow shell ; and the skin folds up over the shell, and is also of an orange-yellow color, 1 Dr. W. Breitenbach, in Popular science monthly, January, – precisely the same color as that of the pen

1885, p. 365, mentions vaguely some nudibranch that imitates the sca anemones upon the stems of Sargassum.

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