Sudden Transformation Research Articles

Conspicuous displays in two species of Australian stick insects

Summary Under certain conditions, sharp tapping to the metasternum and anterior abdominal sternites causes both sexes of the normally procryptic Australian stick insect Eurycnema goliath (Gray) to face the source of disturbance and to display the vivid red undersurfaces of the remigia of the wings, and tegmina and a pair of eye-like spots on the metacoxae. Then the metathoracic legs are rapidly struck togethe once or a number of times, each strike being accompanied by a swishing sound apparently produced by wing movement. A somewhat similar reaction was noted in a female of the stick insect Tropidoderus childrenii (Gray) which has no red. It is suggested that this reaction is defensive, enabling the insect sometimes to bluff predators by undergoing a sudden transformation from a procryptic appearance to a startling pseudoaposematic one.

Contribution of metallurgy to the origin of meteorites: Part I—Structure of metallic meteorites, their composition and the effect of pressure

The composition and structure of metallic meteorites accord with a mechanism of their formation by slow cooling from elevated temperatures under conditions of high pressure. These conditions produced the Widmanstatten pattern in 6–13 per cent Ni-Fe compositions. At some time in their history and at a temperature not higher than 300–400°C this pressure was suddenly changed, accompanied perhaps by a temperature rise followed by comparatively rapid cooling. Approximate times necessary to form the Widmanstätten pattern at several temperatures are calculated. These are estimated from diffusion rates in nickel-iron alloys and from the time of heating required at high temperatures to erase the Widmanstatten pattern (twenty or more hours at 1000°C). From the calculated values it is concluded that within the age of the solar system (3 × 10 9 years) equilibrium could not have been achieved below 300–400°C. In octahedrites, average observed composition of taenite (gamma phase, 30 per cent Ni) and of kamacite (alpha phase, 6 per cent Ni) is evidence according to the phase-diagram of equilibrium at a temperature of 500°C. Nevertheless, taenite variable in composition from edge to centre indicates final stages of Widmanstätten figure formation at a lower temperature range where restricted diffusion prevented homogeneity within the time available. This discrepancy is reconciled by effects of high pressure which lower the gamma-alpha transformation temperatures and the corresponding temperatures for Widmanstatten figure formation. If the prevailing lower equilibrium temperature was about 300°C, the necessary pressure is calculated to be about 10 5 atmospheres. Pressures of this magnitude suggest conditions in the interior of a planetary body. Pressure also accounts for absence of Widmanstätten patterns in meteorites containing more than about 12–13 per cent Ni. These alloys (nickel-rich ataxites) remained for the majority of their extraterrestrial existence in the gamma state. Subsequent fragmentation into smaller bodies released pressure and the alloys either transformed simultaneously into metastable α 2phase, or cooled relatively rapidly through the transformation temperature, forming a mixture of alpha and gamma phases. Meteorites containing more than about 27 per cent Ni contain all taenite which accords with laboratory experience showing that 34 or more per cent Ni-Fe alloys resist transformation under all conditions of cooling or heat treatment. Sudden release of pressure, as by changing distortional stresses or fragmentation of the parent body, accounts in major part for the metallographic structure called plessite. Reduction of pressure momentarily transplants gamma alloy to the alpha-gamma region of the phase diagram resulting in transformation to metastable α 2phase which is an acicular or martensite-like transformation product analogous to structures produced in similar laboratory alloys by thermal quench. Heating of α 2phase within the alpha-gamma region (or slow cooling from this region after transformation) results in a mixture of finely divided alpha and gamma phases either unresolved or granular as observed under the microscope. These products correspond to unresolvable, fine and coarse plessite. Acicular kamacite observed in some meteorites is also explained by sudden transformation occurring through pressure changes. Rapid cooling is not an equivalent explanation, because most original meteorite masses were too large to cool at the required rapid rate.

On Phase Changes of Bose-Einstein Fluid Models

It is shown that all Bose-Einstein (B.E.) fluid models investigated thus far undergo first-order transformations in phase space. The ideal fluid condenses smoothly, e.g., without any possibility of supersaturation, insofar as its thermodynamic characteristic functions and their first derivatives, with respect to the independent variables, are continuous along the transition or saturation curve. The non-ideal B.E. fluids considered, in which attractive interatomic forces averaged over the volume of the fluid are assumed to operate, undergo sudden condensation strictly similar to that exhibited by ordinary fluids in coordinate space. This process is accompanied by the occurrence of discontinuities of the first derivatives of the characteristic functions. By introducing a suitable repulsive interatomic force, smeared over the volume of the fluid, the smooth condensation of the ideal fluid is changed to a phase transformation of the third order. Here the second derivatives of the characteristic functions exhibit discontinuities along the transformation curve. The same interatomic force lifts the order of the sudden first-order transformation by changing it to a second-order one. This is accompanied by the appearance of the lambda-point type discontinuity of the constant pressure heat capacity along the transition or lambda line. The interplay of forces of parallel and opposing tendencies in modifying the nature of a phase transformation without changing its order and in lifting or lowering their order is thus brought out in these studies over B.E. fluid models. The bearing of these results on the problems connected with the thermal properties of liquid helium is touched upon briefly.

PERITONEAL EXUDATE

The existing methods for diagnosis of various conditions affecting the peritoneum have not been uniformly satisfactory. The deficiency in the exact procedures has been felt especially in certain situations such as the recognition and differentiation of primary and secondary peritonitis in children, the determination of the bacterial species in the primary type and the separation of irritative from infectious conditions of the peritoneum. Even less adequate are the available means of establishing prognosis of a phase of peritonitis. The degree of bacterial activity within the peritoneal cavity, especially in the earlier stages of an infection, does not produce clinical manifestations comparable to the potential damage of which the bacteria are capable. The sudden transformation of a patient's condition from a relatively benign to a critical state is by no means as unexpected as the outward manifestations would indicate. The major activities of the bacteria occur within the confines of the

XI. The Babylonian Conception of the Logos

In Greek philosophy the word λόγος, which by derivation and usage meant speech, discourse, spoken word, assumed at an early period in the history of Greek thought the meaning reason, thought, mind. It is so employed, apparently, first by Heraclitus of the Ionian school at Ephesus. There seems to be in the region of purely Greek thought and religion no conception of λόγος or uttered word of the gods which could have suggested its identification with universal reason, first principle and cause of all things as variously employed in Greek philosophy. Rumour was called Ὄσσα Διóς ἄγγελος, “Rumour the messenger of Zeus,” who goes about stirring up strife. And she is the messenger or dame rumour, Ὄσσα δ'ἄρ' ἄγγελος, who hastens swiftly with evil news, the Fama of Roman mythology. We must suppose, if the Ionian philosophers identified Word with cosmic reason and first principle, that they were induced and influenced by some well-known semi-philosophical use of the term “Word of the gods” as the personification of divine agency. It is wholly inconceivable that the Greek language permitted a sudden transformation of one of its most ancient and perfectly understood words without adequate cause. The etymology and ordinary meaning of λóγος afford no remote suggestion of a divine agent, a first principle. The philosophers certainly did not seize upon it arbitrarily for the most important term in the expression of their thought.

Lamarck versus Weismann

I SHOULD like to call the attention of those interested in organic evolution to a remarkable passage in Mr. Wallace's recent volume on “Darwinism.” This work is throughout an argument in defence of Darwinian principles, in their original unmodified form as stated in the “Origin of Species,” in opposition to all recent criticism or development of those principles. And yet on p. 129 the author publishes the following passage:—“Now the eyes of these fish (Pleuronectidæ) are curiously distorted in order that both eyes may be on the upper side, where alone they would be of any use. It was objected by Mr. Mivart that a sudden transformation of the eye from one side to the other was inconceivable, while if the transit were gradual, the first step could be of no use since this would not remove the eye from the lower side. But, as Mr. Darwin shows by reference to the researches of Malm and others, the young of these fish are quite symmetrical, and during their growth exhibit to us the whole process of change. This begins by the fish (owing to the increasing depth of the body) being unable to maintain the vertical position, so that it falls on one side. It then twists the lower eye as much as possible towards the upper side; and the whole bony structure of the head being at this time soft and flexible, the constant repetition of this effort causes the eye gradually to move round the head till it comes to the upper side. Now if we suppose this process, which in the young is completed in a few days or weeks, to have been spread over thousands of generations during the development of these fish, those usually surviving whose eyes retained more and more of the position into which the young fish tried to twist them, the change becomes intelligible.”

Cases of Masturbation (Masturbatic Insanity)

There are exceptions to the rule that all male masturbators are shy with regard to the female sex, and at all times. It is true that the majority are so in the earlier periods of their vice, and as long as definitive mental disease has not set in. In some cases where such disease has become established, a sudden transformation from bashfulness to brazen effrontery, and from timidity to bold, insulting and lascivious demeanour, is noticed. These patients exaggerate the characteristic, so happily drawn by Oliver Goldsmith in “She Stoops to Conquer,” of a certain class of men who are heroes before barmaids and cowards before refined females. In exceptional instances, the masturbatic lunatic is as brutally indecent to those of a higher as to those of a lower station. Godding relates a case of this kind in graphic language in his “Two Hard Cases.”

XVIII. On the development of Carcinus mænas

The author, after noticing the history of the subject, and the opposition which the assertion, “that the Zoë of naturalists is the larva of a common crab,” received, traces the progress of the development of the animal from the Zæa to the adult, and endeavours to demonstrate, that from the youngest to the most perfect form, the changes are the result of no sudden transformation, but produced by a gradual series of alterations contemporary with every succeeding moult; that the Zæa is connected with the Megalopa , and the latter with the adult by many intermediate gradations, each in itself scarcely appreciable, and progressively approximating nearer and nearer the more perfect stages. The author asserts that the development is earliest and most complete anteriorly; that when first born, the seventh or posterior segment of the head, one or more of the posterior segments of the pereion (thorax), and the penultimate of the pleon (abdomen) are wanting in the brachyurous Decapods; but that this general law loses somewhat of its force in the descending scale of development; and as it becomes less persistent, the animal approximates in the larval condition nearer to the form of the adult type; while on the other hand, the same appears to be a constant law of the depreciation in adult forms, as exhibited in the more or less aberrant Amphipoda, such as Cyrtophium, Dulichia , &c.