640 THE RESPIRATION AND [pt. m 



quotient and the heat production. He did not devote much attention 

 to analysing his oxygen data, since they were obtained only as a 

 means to an end, but Bialascewicz & Bledovski showed later that 

 they fell on a parabolic curve which was fitted by the equation 



x=kfi + a, 



where x is the respiratory rate at time t, a the rate in the case of the 

 unfertilised egg, and k a constant. They drew no theoretical conclusion 

 from this, nor did they give the constant in question. 



So far all the workers mentioned have been in agreement con- 

 cerning the effect produced on the oxygen consumption of echino- 

 derm eggs on fertilisation. The first discordant voice was that of 

 Loeb & Wasteneys, who in 1 9 1 2 reported that the eggs of the star- 

 fish (species not given) took up no more oxygen after fertilisation 

 than before. The measurements were made by Winkler's method, 

 and the number of experiments described was small, so that the 

 paper did not attract much attention until Faure-Fremiet's similar 

 results with Sabellaria. Later still, Barron & Titelbaum found no rise 

 in respiratory rate on fertihsation in Nereis. The work on the starfish 

 has been confirmed by Barron. That there is a tremendous rise in 

 metabolic rate, however, during the early cleavage stages of most 

 echinoderm eggs cannot now be doubted, although the shape of the 

 curve in the few minutes after fertilisation is still open to revision 1. 



Much interest attaches to somerecentexperimentsof Carter in which 

 the effect of the egg-secretions upon the spermatozoa were studied. 

 The known factors here are: (i) Lillie's effect — the agglutination of 

 spermatozoa; (2) Glaser's effect — the lipolytic action (see Section 

 14-3); and (3) Gray's effect — the increase in oxygen consumption 

 of the spermatozoa. This increase was not found by Carter to follow 

 the same laws as Gray had stated, i.e. there was no falling off of 

 rate (unless the sperm cells were unripe) but on the contrary a 

 constant uptake. This constant uptake was uninfluenced by thyroxin 

 although the falling uptake of unripe cells was increased by that 

 hormone. As iodine is a well-known parthenogenetic agent, there 

 are some possibilities tliat iodine or a thyroxin-like body is contained 

 in egg-secretion. 



1 It is interesting to note that increased respiratory rate on fertilisation has been re- 

 ported for the minnow (Boyd), the silkworm (Ashbel), the tunicate, Ciona intestinalis 

 (Runnstrom), and various amphibians (Bialascewicz & Bledovski; Parnas & Krasinska). 



