250 THE BIOLOGY OF HYDRA : 1961 



Fig. 4. Cultured cells washed with artificial sea water. Stained with 

 periodic acid Schiff's. Magnification 900x. 



tion of these particles can be controlled, observation of mitosis 

 in developing clones is impossible. 



The cells, particularly those toward the center of the clone 

 in Figure 3, are surrounded by a red staining, carbohydrate-con- 

 taining material which apparently acts as an intercellular cement. 

 It can be weakened by both lysozyme and EDTA, but these agents 

 even in combination do not result in complete separation of the 

 cells. Since lysozyme functions as a i8(l-^4) N-acetyl hexosamini- 

 dase (8), the presence of this carbohydrate derivative in the 

 material appears likely. The material is not susceptible to the 

 chitinase of Helix pomatia, hyaluronidase, nor trypsin. The action 

 of EDTA suggests either the presence of bridges formed by diva- 

 lent ions or possibly the activation of the lysozyme-like enzyme 

 that has been detected in the secretions of these animals (6). 

 Pollak's trichrome stain (9) has also been used in studies of this 

 material. It is again stained red. This staining reaction is given 

 by elastic fibers. Mucus assumes a green coloration by this stain- 

 ing procedure. It appears likely that the material in question is 

 other than mucus. Until the nature of this material is better under- 

 stood, the methods for its degradation are available, quantitative 



