Protoplasmic Streaming — Relation to Gel Structure 145 



D. BEHAVIOR OF UNICELLULAR PIGMENTARY EFFECTORS 



Recently, experiments have been started to determine the effects 

 of pressure upon the ebb and flov/ of pigment granules as it occurs 

 in the melanophores of Fundulus (Marsland, '40) . As yet the 

 results are far from complete, but there are clear indications that 



1^*9 



^ 



^ # i^ 



Fig. 7. Solation of the stiffer "cleavage gel" by pressure. All of these eggs 

 were centrifuged simultaneously for 2.5 minutes at the time when 50 percent 

 of them displayed furrows. The E (experimental) samples were at 7,000 Ibs./in.", 

 whereas the control (C) eggs were at atmospheric pressure. The solation of the 

 cortical gel of the pressure specimens is indicated by the pigment zones at the 

 centrifugal ends, and by the fact that all pigment has been thrown out of the 

 hyaline zones. 



this type of streaming may also involve gelational phenomena. These 

 results, if borne out by further work, may provide a basis for decid- 

 ing M^hether the unicellular pigmentary effector is to be regarded 

 as a modification of visceral muscle (Spaeth, '16) or as an amoeboid 

 type of cell (Hooker, '14) . 



(1) Suppression of the "contraction" phase of the pigmentary 



response 



In this type of experiment the isolated scale of Fundulus v/as 



immersed in N/10 KCl solution and exposed to various degrees of 



compression in the microscope-pressure chamber. At atmospheric 



