THE LIVING SUBSTANCE. 129 



the magnet rather than of the fingers that hold it; or even 

 despotic chemical and physical interactions. A taking of one 

 sort of thing from a number of associated and mingled oppor- 

 tunities, — this is all the physicist or chemist biologist need 

 suppose is claimed at this point. 



At times, the substance as organism selects or accepts 

 materials which some specialized sentinel area within it re- 

 fuses to pass, compelling an organism to reject them second- 

 arily. There are certain areas which seem to be detailed to 

 serve the organism thus and to pass for universal needs of 

 the substance as such upon material admitted within it. In 

 this connection the instance cited of expulsion of bacteria by 

 a Vorticella, and of regurgitation by rotifers of their food, 

 may again be brought into play. Every one knows the drastic 

 action taken at times by different areas of the human body 

 with respect to wrong sorts of internal environment. The 

 most curious of substance devices to rid itself of undesirable 

 internal conditions, is found in scavenger areas — leucocytes 

 and phagocytes — which are so individualized that they select 

 for their own specific environment what is deleterious to the 

 substance in general. They are also used to take up surplus 

 material of various sorts which interferes with normal activities 

 of areas or the organism. Their function is doubtless homolo- 

 gized for the substance as such by migrant currents and filose 

 processes of the interalveolar stuff. 



That the organism makes even fatal mistakes at times in 

 choice of its environment is true, but this is generally caused 

 by lack of perfect subordination of the function of areas to 

 the needs of the organism as such, for these by their very 

 emphasis of irritable function may be led, for their own satis- 

 faction, to wrong the rest of the mass ; or there may be in- 

 escapable physical and chemical affinities which decide the 

 matter, and the organism be taken by surprise ; or there may 

 be an abnormal state in the purveyor area. Deleterious sub- 

 stances that have gone too far to be returned are often hur- 

 ried through the organism, or surrounded by some corrective 

 or insulating substance which prevents their doing harm ; or 

 again, if harm be inescapable, the powers of the substance are 



