PHYSIOLOGICAL CHARACTERISTICS OF AXIATE PATTERNS 123 



ceptible to loss of blood and experimental conditions. Since his determina- 

 tions were made "a few hours" after section and were not repeated on the 

 same lots at different periods, they are without definite significance in rela- 

 tion to the gradient problem, except in so far as they indicate that anterior 

 and posterior regions have undergone depression since section. 



These results with Nereis and the views advanced in connection with 

 them led Hyman (1932a) to undertake a re-examination of oxygen up- 

 take in N. virens with the Winkler method. She finds that during the first 

 3 hours after section the rates are irregular but that from 3 to 9 hours after 

 section the U-shaped gradient is characteristic. Pieces from the posterior 

 region undergo rapid depression in physiological condition after section; 

 consequently, she regards her data as showing a much lower rate in these 

 pieces than the normal. Electric-potential differences and galvanotactic 

 reaction in Nereis are also dependent on freshness of the material (Hyman 

 and Bellamy, 1922). 



Using extremely short pieces in order to eliminate motor activity, Mal- 

 oeuf (1936) maintains that there are no significant diiTerences in oxygen 

 uptake at different levels of an earthworm, the differences observed by 

 others being attributed to differences in motor activity, but presents no 

 actual evidence in support of his opinion. This work, like that of Parker, 

 provides another illustration of the difficulties involved in determining the 

 significance of respiratory determinations in isolated pieces of animals. 

 The effect on respiration of loss of blood and of the large area of cut sur- 

 face in relation to volume is entirely unknown. Maloeuf also finds that 

 total solids, total organic material minus fat, and fat of the body wall and 

 of the whole starved animal, in percentages of wet weight, increase poste- 

 riorly in the preclitellar region and decrease from the clitellum posteriorly, 

 except for an increase in fat at the posterior end. It is of some interest to 

 note that these gradients are essentially the inverse of susceptibility and 

 dye-reduction gradients and of the respiratory gradients found by most 

 investigators. That such gradients are present without any corresponding 

 differences in respiratory rate seems rather remarkable. The anterior re- 

 gions contain less reduced glutathione than other regions, in which the 

 differences are negligible. 



It is sufficiently evident from these data on annelid respiration that a 

 single set of determinations on pieces after section does not afford a basis 

 for any definite conclusions, except that further investigation is necessary. 

 Repeated determinations on the same lots at different times after section 

 and determinations on pieces representing different fractions of the body 



