222 THE INDUCTIONS OF BIOLOGY. 



returned to its previous condition : yet it is not as it was be- 

 fore; for now the same poison may be added to it with im- 

 ])unity." ..." The change once effected, may be maintained 

 through life. And herein seems to be a proof of the assimil- 

 ative force in the blood: for there seems no other mode of 

 explaining these cases than by admitting that the altered 

 particles have the power of assimilating to themselves all 

 those by which they are being replaced: in other words, all 

 the blood that is formed after such a disease deviates from 

 the natural composition, so far as to acquire the peculiarity 

 engendered by the disease: it is formed according to the 

 altered model." Now if the compound molecules of the 

 blood, or of an organism considered in the aggregate, have 

 the power of moulding into their own type the matters which 

 they absorb as nutriment; and if they have the power when 

 their type has been changed by disease, of moulding materials 

 afterwards received into the modified type; may we not 

 reasonably suspect that the more or less specialized molecules 

 of each organ have, in like manner, the power of moulding 

 the materials which the blood brings to them into similarly 

 specialized molecules? The one conclusion seems to be a 

 corollary from the other. Such a power cannot be claimed 

 for the component units of the blood without being con- 

 ceded to the component units of every tissue. Indeed the 

 assertion of this power is little more than an assertion of the 

 fact that organs composed of specialized units are capable 

 of resuming their structural integrity after they have been 

 wasted by function. For if they do this, they must do it by 

 forming from the materials brought to them, certain special- 

 ized units like in kind to those of which they are composed; 

 and to say that they do this, is to say that their component 

 imits have the power of moulding fit materials into other 

 units of the same order. 



§ 65. What must we say of the ability an organism has 

 to re-complete itself when one of its parts has been cut off? 



