3O8 WILLIAM SEIFRIZ. 



definition and description of the phenomena observed. We are 

 little better off in choice of words than were the early microsco- 

 pists whose knowledge of protoplasm was fully indicated by such 

 adjectives as viscous, elastic, hyaline, etc. 



In the possible range in consistency between the two extreme 

 conditions of a colloid, i. e., extreme liquidity and the solid state, 

 the writer will distinguish ten degrees of viscosity, namely- 

 watery, very liquid, liquid, slightly viscous, rather viscous, 

 decidedly viscous, very viscous, extremely viscous, gel, and 

 rigid gel- and has employed these expressions, for want of better 

 ones, to describe the comparative viscosity of protoplasm. Their 

 use will eliminate, in part, the vagueness from such general terms 

 as liquid and viscous. 



Protoplasm, which includes "all the living components of the 

 cell-body' (Strasburger, 1891, p. 13), possesses many life- 

 less inclusions which materially affect its consistency, and they 

 must be taken into consideration when the viscosity of proto- 

 plasm is discussed. As hyaloplasm is usually restricted to the 

 hyaline border of non-granular plasma, the term matrix is used 

 to indicate the translucent and more homogeneous fluid in which 

 the various included granules are suspended. 



Protoplasm, as such, frequently possesses a consistency dif- 

 ferent from that of its matrix. The latter may be watery yet the 

 density of the protoplasm in toto markedly greater. It is, there- 

 fore, important to keep clear the distinction between the pro- 

 toplasm as a whole and the matrix in which the various inclusions 



are imbedded. 



MATERIAL. 



The experimentation leading to the following results was 

 carried on in the Harpswell Laboratory at South Harpswell, 

 Maine. The writer wishes to thank the director, Dr. J. S. 

 Kingsley, for the use of a room in the laboratory and for many 

 other privileges enjoyed there. 



The chief problem for the botanical microdissectionist is the 

 obtaining of material delicate enough to permit dissection by fine 

 glass needles. Even the wall of the frail alga Spirogyra can be 

 entered only by the sharpest and most substantial needle that can 

 be made. All in all, the most satisfactory objects for both zoo- 



