DEMONSTRATION OF AXIAL GRADIENTS. 137 



coagulant or fixing action and so far as my observations go at 

 present, the higher the concentration the less frequent is dis- 

 integration. 



BRIEF STATEMENT OF RESULTS. 



The use of the method thus far has fully justified the assump- 

 tion on which it was based, viz., that some relation would be 

 found to exist between the rate of reduction of permanganate by 

 living protoplasm as indicated by the rate or intensity of the 

 stain resulting from deposition of MnO 2 and the physiological 

 condition of the protoplasm, particularly its oxidative activity 

 or capacity. It has been found that the regions indicated by 

 other experimental methods and by structural and functional 

 characteristics of the organism as regions of high oxidation rate 

 are most rapidly or most deeply stained in permanganate and 

 also show the highest susceptibility as regards death and disin- 

 gration of the protoplasm in the proper concentrations. More- 

 over, the delicacy of the method indicates clearly the existence 

 of certain minor differences in protoplasmic and metabolic 

 condition, which cruder methods show less clearly or not at all. 



Thus far permanganate has been used as a staining agent to 

 demonstrate the gradients in various forms as opportunity 

 offered. These forms include algae, protozoa, hydroid and 

 medusa forms, eggs and early developmental stages of hydrozoa, 

 a siphonophore, young actinians, polyclad larvae, eggs and 

 various early developmental stages of sea urchins, and ascidian 

 tadpoles. Some observations have also been made on elongated 

 organs such as the tentacles and branchiae of the polychete, 

 Amphitrite. The results as regards the existence of the gradients 

 agree in general very closely with those obtained in other ways, 

 except as regards some minor points shown less clearly or not 

 at all by other methods. 



In the algae examined each active physiological axis of the 

 thallus begins to stain at the apex and the stain progresses 

 basipetally, but in the older regions of the body irregularities 

 appear as with other methods (Child, J i6b, 'i6d, '170). In 

 monosiphonous branching forms such as CalUthamnium with 

 elongated cells, the progress of the stain along a single cell can 

 often be observed and in such forms also the gradient in proto- 



