OF VITALITY. 99 



of the Sheep; and always with the same results. In the case of 

 the Sheep, the muscle granules were round, so that I could at 

 once distinguish the muscle-vibrios from the tendon-vibrios, 

 because in the latter the granules were elongate oval, even be- 

 fore the tendon fell to pieces in the process of decay, whilst in 

 the former they were spherical. 



Now here we see animals, some high in the scale of being, 

 exhibiting signs of life, that is as far as motion may indicate it, 

 even in the last stages of decomposition. In Aurelia, the signs 

 of life, as exhibited by its cells, (fig. 50,) are more positive 

 than in the other instances ; but we may have various degrees 

 of this kind of proof of vitality, according to the nature of the 

 cells. In the case of Aurelia, the individual cells move by the 

 action of their little arm-like projections ; whereas in Sagitta 

 and the Sheep, the granules of the vibrio-like fibrillae may pos- 

 sibly move by the action of the water as it is absorbed by them, 

 or, what is not in the least improbable, the individual granules, 

 especially in the muscle, may contract and expand, just as they 

 do in the living animal. 



Since, therefore, we have animals whose individual cells, when 

 separated, like so many distinct individuals, exhibit the phenom- 

 ena of life, why may we not also have one-celled animals, exist- 

 ing just above the amorphous stage of decomposition ? Amoeba, 

 (and Rhizopoda in general,) in one sense a one-celled animal, 

 has scarcely a higher state of vitality than the decomposed 

 Sheep-muscle, or Aurelia-cells. Who can say what degree of 

 vitality exists in the hen's egg which is dependent, just as much 

 as the creatures in Prof. Wy man's sealed flasks, purely upon 

 extraneous or physical agency for its development into a chick ; 

 otherwise, if it were not supplied, or acted upon, by this physi- 

 cal agent, heat, it would remain in a low state of vitality, per- 

 haps as low as any decomposing muscle or tendon, and finally, 

 it would decay. 



In the egg we have an uncomposed substance, and in the 

 decaying muscle we have an animal returning to its former 

 uncomposed state. 



