330 



Mr. J. Bretland Farmer. On the Effect of 



through any cause becomes ruptured, or if it softens and swells, the 

 seeds which are thus affected are incapable of manifesting any further 

 evidence of vitality. It appears to me that a fair inference to be 

 drawn from these facts is that the admission of water to the living 

 cells is a potent factor in bringing about their death. 



Jodin* has recently communicated some facts which point to the 

 same conclusion. He exposed seeds of pea and cress to a temperature 

 of 98° C, and found that unless great care had been previously exer- 

 cised to ensure the dryness of the seeds, they were all killed. AMien 

 they had been previously dried he succeeded in subsequently germi- 

 nating 30 per cent, of the peas and 60 per Cent, of the cress seeds. 

 Perhaps the disproportion in favour of the latter may. at least in part, 

 be ascribed to their small size, and consequently to the less difficulty 

 in sufficiently drying the seeds. 



It would seem to follow from what has been said that the instability 

 of the complex molecular structure of which li\dng organisms are made 

 up, may be lessened by appropriate desiccation, but the substances 

 concerned are too complex to render themselves readily accessible to 

 inquiry. It appeared, however, that it might be worth while to study 

 the effects of desiccation on albumin from this point of view. Albumin 

 is not only a highly complex proteid, and perhaps in some respects 

 akin to protoplasm itself, but it is one which gives tolerably definite 

 heat reactions. It is in connection with the last-mentioned point that 

 the new facts in this paper are specially concerned. 



It is of course known that albumin in a watery solution is readily 

 coagulated on heating to a certain temperature. This temperature, 

 however, is not necessarily constant for even one type of albumin, 

 doubtless owing to the readiness with which it undergoes change. 

 Thus albumin obtained from different hens' eggs will often be found to 

 coagulate at different temperatures, and the differences appear, in part 

 at any rate, to be connected with the age of the egg. I have found in 

 the case of freshly-laicl eggs, that the characteristic opalescence which 

 marks the early stages of coagulation may set in as low as 60" C, the 

 clotted coagulum being fully formed at 64° C. The heat was applied 

 by means of a large water-bath, so as to ensure its being as uniform as 

 possible. Another sample of albumin from a different egg tried simul- 

 taneously and under the same conditions, only exhibited opalescence at 

 65*6° C, and coagulated completely at 68° C. 



The albumin on which most of my experiments were made, M'as ob- 

 tained from Merck, of Darmstadt, and was sent as dried egg-albumin. 

 It readily dissolved in water, with the exception of a little flaky in- 

 soluble portion, which was filtered off. The solution had a low coagu- 

 lation-point, the opalescence appearing at 60° C, and the clot at 62° C. 



* ' Coiiiptes Eendus,' 1899. 



