On the result of crossing round with wrinkled peas, with especial reference to their starch-grains

1908 ◽  
Vol 1 (1) ◽  
pp. 472-473
Author(s):  
A. D. Darbishire

One of the characters with which Mendel dealt in his hybridisation experiments with peas was, as is well known, the shape of the ripe seed. Weldon, in his criticism of Mendel’s interpretation of his results, showed that round were not discontinuously distinct from wrinkle peas, but that intermediate shapes connecting these two extremes were not infrequently exhibited. The answer which was made to Weldon’s criticism was that the intermediate shapes were due to spurious pitting or dimpling of the seed, and did not represent an intermediate condition of the germ which gave rise to them. And this answer was shown to be correct by the work of Gregory, who found that the starch-grains of round and wrinkled peas were quite distinct, and that they afforded an infallible test by which the real character of a pea with doubtful shape could be determined. Our knowledge of this subject has not advanced beyond the stage reached by Gregory in 1903; that is to say, we know no more about the inheritance of wrinkledness and roundness than Mendel did, except that each of these two characters is associated with a particular kind of starch-grain. What is the nature of the starch-grain in the hydrid; and how the characters of the starch-grains segregate, if they do so at all, in subsequent generations, are points on which we are at present ignorant. The observations, which I have to record, form the first instalment of an attempt to fill up this gap in our knowledge.


1926 ◽  
Vol 44 (4) ◽  
pp. 483-502
Author(s):  
Louise Pearce ◽  
Chester M. Van Allen

An analysis has been made of the organ weights of normal rabbits exposed to a constant illumination having none of the shorter ultraviolet rays and of other rabbits kept in darkness for periods of 2 to 12 weeks. The environment of constant illumination was associated with a well marked decrease in the relative weights of most organs, and in certain instances this occurred when the organ weights of the controls were becoming increasingly large. There was also an associated effect of stabilization of organ weight. The majority of the organs of rabbits caged in constant darkness also showed a tendency toward decreased and stabilized weights, but these effects were less pronounced than in the rabbits caged under conditions of constant illumination. A notable exception to this general result was the weight of the liver which was markedly increased. The results of this experiment support the conception that there is a relationship between light and the physical state of the animal organism which may be expressed in the concrete form implied by the trend or direction of organ weight.


1913 ◽  
Vol 18 (4) ◽  
pp. 322-346 ◽  
Author(s):  
Frank P. Underhill ◽  
H. Gideon Wells ◽  
Samuel Goldschmidt

Salts of tartaric acid administered subcutaneously to fasting phlorhizinized animals exert a markedly detrimental influence upon the secretory efficiency of the kidney, which is indicated by a greatly lessened output of certain typical urinary constituents. A histological study of the nephritic kidney demonstrates that the salts act specifically upon the epithelium of the convoluted tubules, and to a less extent upon the tubules of the loops of Henle, the glomerules, and interstitial tissue remaining unharmed. In the disintegrative process taking place, vacuolation first occurs, is rapidly followed by necrosis, and finally the dead cells or their debris may entirely fill the lumina of the tubules and form granular and hyaline casts. There is no strict relation between the dose of tartrate and the extent of damage inflicted. While large doses invariably induce a well marked response small doses may at times produce effects equally significant. Tartrates introduced into fasting animals call forth symptoms practically identical with those observed in fasting phlorhinized animals. It is therefore apparent that in the establishment of the pathological condition under discussion phlorhizin is without significant influence. Neither the liver nor the adrenal exhibits any detrimental effect from the injection of tartrates. The introduction of tartrates by way of the mouth to fasting rabbits is not nearly so effective in the production of nephritic symptoms as the administration of much smaller doses subcutaneously. In general, under the former circumstances the initial stages only of epithelial disintegration of the convoluted tubules obtain, which, however, are scarcely sufficient to account for the rapidity with which death usually ensues. Although in well fed animals distinct pathological changes in the kidney are induced by the introduction of tartrates per os, these abnormalities are less in degree, but similar in kind, than those provoked under like conditions in the fasting animal. When tartrates are given subcutaneously to well fed rabbits the effects evoked are somewhat less pronounced than when the salts are injected into fasting animals. From these facts it is evident that the state of nutrition plays a part in the development of tartrate nephritis. It is indicated that the introduction of a sufficiency of alkali to animals in a state of fasting permits a greater elimination of urinary constituents during tartrate nephritis than obtains under similar circumstances when the alkali is omitted. Histologically there is evidence that the administration of alkali exerts a slight modifying action.


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