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The objects of this work were to reinvestigate and extend the results announced in a brief note published in 1925 (Murray and Huxley, 1925a). In this paper it was concluded that isolated fragments of the limb buds of the fourday chick are able to self-differentiate when Iiving as grafts on the chorio-allantoic membrane of older chicks; that the bud of the four-day chick is a mosaic; it was hinted that each of the morphological regions of the limb (femur, tibia-fibula, etc.) is represented by a Single piece of the mosaic; that no regeneration or regulation occurs in fragments of the bud, except that it was concluded that if a grafted fragment contains only part of a piece of the mosaic, that part could so regulate its future development as to form the complete morphological region of which it was originally a part, so that a fragment of the bud which contains part only of the region Which would normally form femur will, when growing as a graft, form a complete femur. It will be seen that the results of the present work uphold and confirm the tentative conclusions previously advanced, except in regard to the last point (regulation). A considerable amonnt of further information has also been obtained bearing on tile factors concerned in the development of the form of bones and joints.
1. In investigating a spontaneous epidemic disease of rabbits, a micro-organism was isolated in pure cultures which reproduced the characteristic lesions of the natural disease.
2. The bacteriological characters of this bacillus are described and the impossibility of identifying it with previously recorded organisms justifies its being considered a new species. The name Bacterium monocytogenes is proposed.
3. Animal passage raised "virulence" when the doses were well chosen, and increased virulence accentuated the production of necrotic lesions. Overwhelming doses of culture resulted in lowering of "virulence" by animal passage.
4. Bacterium monocytogenes, in doses less than the M.L.D., produced in the circulating blood of rabbits an extreme monocytosis. The responses of the other white cells. were either transient or inconstant.
5. Repeated doses of the organism became progressively less effective as stimuli to large mononuclear production.
6. The cell content of the thoracic duct did not reflect the high degree of monocytosis in the circulating blood.
7. On intrapleural injection of peptone broth and B. coli, the cells of the resultant exudate were primarily polymorphonuclears, even though the circulating blood showed a high monocytosis. With intrapleural injection of B. monocytogenes, when the blood stream was rich in large mononuclears, a pleural exudate containing 30 per cent of these cells was obtained.
8. Phagocytosis experiments in vitro showed that the large mononuclears, while they phagocyted B. coli indifferently, took up B. monocytogenes with an avidity in all respects equal to that of the polymorphonuclear neutrophiles.
The results of the pre:lent investigation may be summarized as follows: (1) The heat content of carbon steels at high temperatures was determined by the mixture method, while the oxidation of the specimen was prevented by passing a purified hydrogen gas through the furnace. The specimens were twelve kinds of steels with different carbon contents from 0.09 % to 2.84 % and the range of temperature was 23~250°C. (2) According to A. Meuthen, the specific heat is constant below the A1 point, but the present writer showed that the specific heat is only constant above the A3 point, and that below this point, it increases with the rise of temperature. (3) The quantity of heat for the dissolution of pearlite in iron was determined by measuring the heat content above and below the A1 point. This heat increases proportionally with the content of carbon, reaches a maximum at 0.9 percent and ends at 6.7 percent. For the dissolution of I gr. of carbon in iron, a heat of 1760 calories is required, while, 16.1 calories are necessary for the dissolution of 1 gr. of pearlite in iron. (4) From the heat content-concentration curve, it was found that, the mean specific heat of cementite increases with the rise of temperature; it is 0.149 at 150°C and 02.20 at 850°C. (5) It was observed that the specific heat of the carbon poles with 98 %C increases almost linearly up to 700°C, and afterwards its rate of increase gradually diminishes. (6) It is confirmed by experiments that the A1 transformation is a function of temperature and time, but that the A2 transformation is a definite function of temperature only. (7) From the heat content-concentration curves, the heat of transformation from martensite to pearlite was obtained and found to be proportional to the carbon content. (8) The heat of transformation from austenite to martensite, or that from martensite to pearlite, increases proportionally with the content of eutectoid carbon. The heat of transformation from austenite to martensite for a eutectoid steel amOlmts to 5.9 calories.