THE BEGINXINGS OF LIFE. 337 



all the vital influences of the organism of which it 

 formed part, what wonder is it that the new-born parti- 

 cles which are still evolved should assume the familiar 

 shapes of such units {Bacterid) as appear in organic 

 solutions outside the body ; or that some of the minute 

 particles which existed in the blood, before death was 

 close at hand, should alter their destination and develop 

 into Bacteria^ just as the milk-globules develop into 

 large Fungus-germs ? It is also quite possible that a 

 heterogenetic change of some kind may overtake red 

 and white blood-corpuscles when they are liberated 

 from the vital influences of the organism in which they 

 have been produced, and also occasionally within the 

 living organism itself. On this subject, however, we 

 have at present very little evidence 1. 



^ White blood-corpuscles are practically young Amoebae, and there is 

 no saying what changes they may not occasionally be capable of under- 

 going. Gregarince, which are so very abundant in the bodies of lower 

 animals, and which are closely allied to Amoebae, may perhaps in many 

 cases be derived from the transformations of such coqauscles. Again, 

 red blood-corpuscles are very similar in many respects to the chlorophyll 

 vesicles of AlgcB and CharacecB, although the latter are probably much 

 less specialised in composition. But it will appear further on (Chap. XX) 

 that the transformations of such chlorophyll vesicles are often of the 

 most startUng description. Quite recently, Mr. Ray Lankester (' Quar- 

 terly Journal of Microscopical Science,' 1871) has described a peculiar, 

 though small and simple, ciliated Infusorium which he found in the 

 blood of certain frogs ; whilst Dr. Boyd Moss (' Monthly Microscopical 

 Journal,' Oct. 1871) has described a similarly simple Infusorium found 

 in the blood of a Ceylon red deer on several occasions. It seems to me 

 more easy to suppose that such organisms should have arisen by a 

 heterogenetic process, than from ' germs ' of delicate, externally existing 

 organisms of this kind, which had not only made their way into the 

 VOL. II. Z 



