182 0. P. Bellinger. 



the formation of the fine pseudopods of many ^'Sarcodina," find no 

 explanation. (Biitschli, p. 198.) He suggests (p. 208) that muscu- 

 lar contraction may possibly be explained by the above hypothesis. 

 The fibrils are there composed of a row of alveoli instead of being 

 simple threads. 



Since Biitschli's publication many observers have described proto- 

 plasm as a "Schaum." Thus, Andrews (1897), after a most exten- 

 sive microscopic study of living protoplasm, decides that all the 

 phenomena observed finds an explanation in Biitschli's Schaum- 

 structure. Crato, in 1892, '95 and '96, finds the foam structure to 

 hold for plant protoplasm. Erlanger (1897) expresses himself in 

 favor of this theory. Degen (1905), after a series of investigations 

 on the action of the contractile vacuole, is of the opinion that proto- 

 plasm is alveolar. The alveoli of his photographs, it seems, however, 

 might be interpreted as meshes of a reticulum. 



Study of Cilia. 

 Point of Vieiu. ■ 



A number of eminent investigators, Biitschli, Rhumbler, Jensen 

 and others, have taken Verworn's standpoint, that "Die lebendige 

 Substanz der rhizopodoiden Zelle mit ihrer Bewegung muss Aiis- 

 gangspunkt fiir die Untersuchungen der Contractionserscheinung 

 sein. Es heisst die Losung des Contractionsproblems unnothig er- 

 schweren, wenn man die Behandlung bei der quergestreiften Muskel- 

 zelle beginnt, wo die Differenzirung der lebendigen Substanz und ihre 

 einseitige Anpassung an eine bestimmte Leistung ihren hoclisten 

 Entwicklungsgrad und ihre grosste Complication erreicht hat," and 

 have approached the problem from this point of vieM\ Yet the out- 

 come of their investigations in complex fluids and microscopic foams 

 has been unsatisfactory and has led to widespread confusion of our 

 notions of contractile structures. For pure contractile tissue, micro- 

 scopically speaking, our simplest structure is the cilium. Here, with 

 the protoplasm accessible for experiments with all kinds of reagents, 

 if anywhere, we should find the key to the structure of contractile 

 protoplasm. If, in applying the methods for the demonstration oi 

 cilia to the protoplasm of the cell, structural elements are demon- 



