166 ADDISON, ON BLOOn-COHPUSCLES. 



is nothing more than would a j)nori have been expected ; and 

 it will be found actually to be so : the external conditions and 

 position seem very distinctly to regulate the state of the 

 plant. 



The innate tendency of any one form to continue and to 

 multiply in that form is well shown in all stages of this 

 plant ; whether in the free segmenting gonidial stage, in the 

 early, half-grown, or mature linear, or later on in any stage 

 of the collateral mode. Of this fact proofs may be obtained 

 in every specimen. This property, probably, is possessed by 

 most, if not all, the lower algaj ; and it is this which has 

 doubtless tended to divide into distinct species and genera 

 forms which should have been but the links of a single chain. 

 And the knowledge of this should have a strong influence on 

 our manner of studying these lower forms. 



Notwithstanding that this tendency is frequently observed, 

 there is no doubt but that, the circumstances under which the 

 plant is placed altering, a change of the kind of growth may 

 be readily induced in it, which again will continue till other 

 disturbing influences affect it. 



In regard to the lower forms of life it may with good reason 

 be asked, 'MYhat, then, is a species?'^ Before an answer 

 can be given, another question must be answered — " Through 

 what cycles of variation in form, colour, and mode of growth, 

 can an organism pass?" The study of the entire life- 

 history is the only means towards its solution of the value of 

 " species." 



On Changes in the Properties of the Red Corpuscles of 

 Human Blood in relation to Fever. By William 

 Addison, M.D., F.R.S. 



All animal secretions are produced by the agency of cells 

 or cellular- bodies. 



To establish this proposition it is not necessary to discuss 

 the merits of the Cell Theory, to inquire whether the pre- 

 dominant force which determines secretion resides in the 

 membrane, the nucleus, or granulous contents of the cell. 

 It is Sufficient, if cells or cellular bodies be absent, that 

 secretion, and necessarily the qualities which individualize 

 secretion, are absent too. 



