420 COSMIC PHILOSOPHY, [pt. il 



phenomena by imagining some entity behind it, the activities 

 displayed by living bodies were thought to be explained 

 when they were called the workings of a "vitnl principle" 

 inherent in the living body, but distinct from it and surviv- 

 ing unchanged amid its manifold alterations. If a stone 

 falls to the ground, that is a manifestation of gravitativo 

 force ; but if a stream of blood come rushing through a 

 capillary tube and certain compound molecules of albuminous 

 matter are taken from it and retained by the adjacent tissue, 

 then, according to the vitalistic theory, the " vital principle " 

 is at work. During life this "principle" continues to work; 

 but at death it leaves the organism, which is then given up 

 to the mercy of physical forces. Such was the theory of life 

 which was held by many physiologists even at a time within 

 the recollection of persons now living; and it doubtless still 

 survives in minds uninstructed in modern science. So long 

 as this doctrine held undisputed sway, the belief that all 

 life proceeds from life was not likely to be seriously im- 

 pugned. For whence, save by derivation from some other 

 " principle " like unto itself, could this mysterious " vital 

 principle " arise ? Besides all this, the Doctrine of Evolution 

 had not yet been originated ; all things were supposed to 

 have been created at once in their present condition ; and, as 

 no need was felt of explaining scientifically the origin of 

 the highest organisms, so there was no disposition to inquire 

 into the origin of those lowest in the scale. A series of 

 separate creative acts was supposed to account for the whole. 

 Strengthened by these metaphysical conceptions, the doc- 

 trine omnc vivum ex vivo remained in possession of the field for 

 two centuries Phenomena apparently at variance with it — 

 such as the occasional discovery of animalcules in closed 

 vessels — were disposed of by the hypothesis, devised by 

 Spallanzani, that the atmosphere is full of invisible germs 

 which can penetrate through the smallest crevices. This 

 hypothesis is currently known as "panspermatism," or the 



