THE BEGINNINGS OF LIFE. 225 



and we believe it to be in the highest degree probable 

 that the fully developed leucocytes or plastides which 

 were seen in the later examinations had arisen out 

 of the growth and development of the mere organic 

 specks met with in the earlier stages of the enquiry. 



This latter view receives the strongest support from 

 observations that have been made as to the nature and 

 mode of origin of the white corpuscles of the blood. I 

 have obtained some very striking evidence on this sub- 

 ject from the study of specimens of blood taken from 

 two persons suffering from Leucocythaemia, though I had 

 previously been tending towards the same conclusion 

 from a careful study of its condition in other states of 

 disease in which the white corpuscles existed in undue 

 proportion. In these two cases the number of the white 

 was equal to that of the red corpuscles : instead of the 

 two kinds of elements existing in the normal propor- 

 tion of about one of the former to three hundred of the 

 latter. The other most striking feature in the speci- 

 mens of blood from these patients was the extreme 

 variability in the size of the white corpuscles some 

 being nearly twice as big as usual, whilst others were 

 seen of all intermediate sizes between this and a mere 

 protoplasmic speck 40 ooo" in diameter. The corpuscles 

 also presented different aspects, the largest of them 

 appeared to possess a cellular structure there were 

 slight evidences of a boundary wall, and numerous 

 large protein granules within, more or less completely 

 concealing a faint ovoid nuclear-looking body. This 



VOL. i. Q 



