Abstract
LONDON. Royal Society, June 16.—Sir Archibald Geikie, K.C.B., president, in the chair.—D. Thoday: Experimental researches on vegetable assimilation and respiration. VI.—Some experiments on assimilation in the open air. In these experiments Sachs's half-leaf dry-weight method has been employed, with modifications suggested in a previous paper for avoiding errors due to shrinkage of the insolated half-leaves. Turgid leaves of Helianthus annuus were found in bright sunlight to increase in dry weight 17 mg. per hour per sq. decim.; thus Sachs's high value is confirmed. Even a slight loss of turgor, however, was accompanied by a diminution in the rate of increase. For this high rate of assimilation a leaf-temperature of 23° C. to 24° C. is probably required. It is suggested that Brown and Escombe's low results in bright diffuse light indicate that the stomata of Helianthus leaves open to their full extent only in light which is similar in quality to sunlight and approaches it in intensity. Detached leaves of Catalpa bignonioides when fully turgid increased 5-6 mg. per hour per sq. decim. in bright sunlight; in this plant stomata occur only on the underside of the leaf. The effect of detachment from the plant upon the rate of assimilation is considered, and evidence is adduced in support of Sachs's assumption, in the case of H. annuus, that, concurrently with assimilation, part of the products of photosynthesis are translocated from leaves still attached to the plant.—Prof. Ronald Ross and D. Thomson: A case of sleeping sickness studied by precise enumerative methods; regular periodical increase of the parasites disclosed. The enumerative methods referred to consist of modes of detecting blood parasites when very scanty, and of counting them accurately. The methods have been applied to a case of sleeping sickness in the clinic of Prof. Ross in Liverpool for seventy-three days continuously, and have shown that the numbers of T. gambiense in this patient's blood undergo remarkable periodical variations about every seven to eight days. The authors state that, so far as they can ascertain, though the numbers of trypanosomes had been known previously to vary from time to time, the regular periodicity revealed in their case appears to have been overlooked, possibly owing to insufficient methods of counting. The authors report that numerous parallel researches are being conducted, and give a chart.—Dr. C. Todd and R. G. White: The recognition of the individual by hsemolytic methods (preliminary communication), (1) The immunisation of the ox with the red blood corpuscles of other oxen gives rise to the formation of a hsemolytic amboceptor in the blood of the immunised animals. (2) The amboceptor so formed is an isolysin, but not on autolysin. (3) The race of the animal appears to have very little influence on the resulting haemolysins. (4) The serum of an animal so treated acts very differently on the red blood corpuscles of different individual oxen. (5) The sera of different individuals similarly immunised differ from one another in their action on the corpuscles of different individuals. (6) If the serum of a single immunised animal be “exhausted “with excess of the corpuscles of one other individual, the serum loses its power of hsemolysing the corpuscles of this individual, while retaining the. power of haemolysing the corpuscles of many, but not all, other individuals. (7) If, however, a polyvalent serum be made by mixing the sera of a large number of immunised animals, and this serum is exhausted with the corpuscles of any one individual, the serum entirely loses its power of enolysing the corpuscles of this individual, but remains strongly hEemolytic for all other individuals not closely related to the individual the corpuscles of which were employed for the exhaustion of the serum. (N.B.)—It is possible that exceptions may be found, but these have not yet been met with, except in the case of close blood-relations.) (8) The red blood corpuscles of any individual are thus characterised by a definite individuality of their own, and can be distinguished from those of any other individual of the same species.—F. M. Tozer and Prof. C. S. Sherrington: Receptors and afferents of the third, fourth, and sixth cranial nerves. Examination of the several extrinsic muscles of the eyeball in the monkey, cat, and rabbit, shows that these muscles contain, besides nerve-endings of the motor kind, large numbers of receptive (sensorial) nerve-endings, both in the fleshy part of the muscles and in the tendons. Investigation of these by experimental methods shows that all the receptive end-organs, as well as the motor endings, derive their nerve-fibres from the third, fourth, and sixth nerve-pairs respectively. These cranial nerves are therefore not purely motor, as generally supposed, but are sensory as well as motor. The number of afferent nerve-fibres they contain is very considerable. In addition to their sensory and motor supply from third, fourth, and sixth nerves, these muscles and their tendons receive a small supply of nerve-fibres from the ciliary ganglion. This ciliary-ganglion supply is largely, if not wholly, vasomotor in function, and no evidence was found that it is in any way sensorial. Nor does the fifth cranial nerve supply any sensory nerve-fibres to these extrinsic eye muscles. The afferent divisions of the third, fourth, and sixth cranial nerves are entirely proprioceptive in function; the receptive organs they subserve are entirely proprioceptive.—Sir David Bruce, Captains A. E. Hamerton and H. R. Bateman, and Captain F. P.
Article PDF
Rights and permissions
About this article
Cite this article
Societies and Academies . Nature 83, 511–514 (1910). https://doi.org/10.1038/083511a0
Issue Date:
DOI: https://doi.org/10.1038/083511a0