64 PROTOPLASMIC ACTION AND NERVOUS ACTION 



structure of protoplasm is thus intimately bound up 

 with the basic problem of general physiology. 



The problem relates to the nature of the structure 

 in livmg protoplasm. All observers agree that cell 

 structure is profoundly altered by death; disintegration 

 then follows, accompanied by diffusion of the cell 

 constituents into the surrounding medium. As already 

 described, the death of the cell is associated with loss of 

 its normal osmotic properties or semi-permeability; the 

 normal electrical polarization also disappears at the same 

 time; both phenomena are characteristic, and indicate 

 interruption in the continuity of the protoplasmic 

 boundary layer. The most obvious general structural 

 changes occurring in the cell interior at death are of a 

 coagulative kind ; the protoplasm loses its normal trans- 

 lucency and becomes more opaque (death rigor or death 

 coagulation). This effect is seen in the greatest variety 

 of cells and organisms, especially those with translucent 

 protoplasm, as cited above. The protoplasm of muscle 

 cells becomes more opaque and loses its coherency or 

 tensile strength; dying swimming plates whiten and fall 

 to pieces on shaking, and other phenomena of a similar 

 kind are well known to all biologists. Many observations 

 on the postmortem alterations of structure have been made 

 since the introduction of the methods of microdissection. 

 Kite and Chambers describe dying cells as losing their 

 viscidity and as being easily torn to pieces. Chambers 

 describes the isolated nerve-ganglion cells of the lobster 

 as undergoing irreversible structural changes when 

 mechanically injured; the protoplasm then ''sets into a 

 coagulated non-viscous mass which may be broken into 

 non-glutinous pieces." Taylor describes a similar break- 



