370 Erste Sektion : Cytologie und Protozoenkunde. Erste Sitzung. 



Polarity is supposed to be evidence of a permanent structure 

 in the protoplasm. The existence of such a structure is often 

 denied on theoretical grounds by those who look upon proto- 

 plasm as a chemical mixture of complex organic and inorganic 

 Compounds. Writers on protoplasm usually favour either the re- 

 ticular theory, the alveolar theory, or the granulär theory, often 

 as a resultant of the method employed, and the viewpoint, whether 

 morphological or physiological, from which the facts are ob- 

 served. 



The conclusion reached, in matters like these, where Inter- 

 pretation must so largely enter in, is necessarily a resultant of 

 two factors: the observers habit of mind; and the evidence which 

 the object of study presents. But the mental habit, or the ha- 

 bitual viewpoint, often seems to determine what evidences shall 

 be attended to. It may as well be said, that the opinions of such 

 mentally biased observers are of little or no value; and that 

 sc ence would be benefitted if their dogmatizing were taken less 

 seriously. 



The physiologist is so apt to ignore the permanent aspect of 

 things, and so eager to look for the changes which accompany 

 functional phenomena. Such changes are facinating, not only 

 because they are more readily seen, but because they stimulate 

 more strongly the desire to discover an explanation of those 

 changes. Most minds betray a disposition to reduce all pheno- 

 mena to an unit. The habit of mind acquired in the study of che- 

 mistry and physics predisposes the observer to explain all life in 

 terms of molecules and atoms. To account for life in terms of 

 dead matter often seems more satisfactory than to explain life in 

 terms of living units. In the latter case we are apt to feel that we 

 assume what we are trying to explain. Properly considered, how- 

 ever, atoms and molecules are as purely theoretical as are com- 

 binations of these into living units of a higher order. A crystal is 

 no less real because it is something more than a fortuitous con- 

 course of atoms and molecules. If we say that molecules are 

 alive, as some do, we do not simplify matters; for somehow che- 

 mical Compounds have not yet been made to live. „Omne vivum 

 ex vivo" seems to express a fact; and why not accept the fact? 

 There may be an element of time entering in here, which we fail 

 to take note of, in observing the more trancient aspects of our 

 subject. The question then becomes: what are the morphologica] 

 features which protoplasm presents; and what are the physiolo- 

 gical processes by which structure is maintained in the midst of 

 the multitude of changes which functional activity involves? 



In higher forms of life, we usually concede the presence of 

 an organ specialized for the Performance of a function. In these 

 higher forms coordination of organs, which entails a regulär se- 

 quence in their functions, is readily made out; and it seems a 



