DR DAVY ON THE FREEZING OF THE EGG OF THE COMMON FOWL. 513 



abort, is much greater in the early spring, in cold weather, than in the advanced 

 spring and in summer. Very lately an example of this kind occurred. On the 

 26th of January thirteen eggs were put under a hen, a good sitter ; on the 16th 

 of February six of these were hatched ; the chickens produced were strong and 

 healthy ; of the other seven — the aborted — one only was found in a state of advan- 

 ced putrefaction; in three of the remaining there were embryos from 6 to 7 inch 

 in length, and in the other three, though no embryo could be seen, there was an 

 appearance of vessels containing discoloured blood.* During the period of incu- 

 bation for many days there was severe cold ; but then, even in the open air, 

 exposed to the clear sky, the thermometer never fell below 18" Fahr. The hen's 

 nest was under cover. 



Whether the germ can exist, retaining life without vital action of any kind, 

 even at a temperature below the freezing point, is a physiological question, I need 

 hardly observe, more easily asked than answered, and yet surely a question 

 deserving of consideration. If, as some distinguished inquirers maintain, there 

 cannot be force without action, can there be life without it ? or, to quote the words 

 of Mr Paget, giving them in the form of a question, Can there be " a vital princi- 

 ple in organized bodies, such as may enable them, even when inactive and dis- 

 playing no other sign of life, to resist passively the influences of physical forces?" 

 Another question, of no less difficulty, is, Whether the germ can resume vital 

 action after having been frozen? I will only remark, that the mere act of 

 freezing does not necessarily imply inaction, at least the absence of chemical 

 charge, for I have found ammonia in an unmistakeable manner evolved from 

 the fresh egg when frozen. And further, provided the structure of the parts — 

 that of the yolk and germ for instance — be not materially altered, and from 

 freezing, the structure of the yolk, we have seen, has not been apparently changed 

 is not the condition of the germ similar to that of the ear of the rabbit and the 

 wattles of the cock, which Hunter found could be frozen without mortifying. | 



* In one of these only, were there marks of incipient putrefaction. It is noteworthy, that in 

 three of these, the albumen was firmly coagulated, as if it had been boiled ; it was quite white, and 

 showed its usual alkaline reaction. The yolk was also coagulated, but less firmly. Mr Hunter 

 states (op. cit. p. 29) " that if an egg was not hatched, that egg became putrid in neai-ly the same 

 time with any other dead animal matter." This does not accord with the results just mentioned, 

 nor with others which I have obtained. In many instances I have found the aborted eggs free 

 fi'om putridity after incubation ; whether an embryo could be detected or not, there was commonly a 

 blending of the yolk and white, and the formation of a fluid, almost entirely destitute of 

 viscidity. Such an admixture is certainly favourable to the putrefactive change. 

 t Phil. Trans., for 1778, p. 34. 



Lesketh How, Ambleside, 

 March 17, 1864. 



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