SECT. 12] GYCLOSES, PHOSPHORUS, SULPHUR 



1235 



nitrogenous sulphur-containing bodies was more intense than at the 

 beginning. The sulphur/nitrogen ratio is shown on the same graph 

 as the phosphorus /nitrogen ratio in Fig. 385. 



Somewhat more extensive studies on the sulphur excretion of the 

 chick embryo were made by Takahashi in 1928, who estimated the 

 sulphates in the developing hen's egg, using Folin's method. In the 

 yolk, white and amniotic liquid these were never found, but they 

 were always present in the em- 

 bryo itself and in the allantoic f ®T°'^' '"'.P^^^, ^, h U . u u- 



•^ -g O Inorganic sulphate? Takahashi 



hquid. Fig. 399, which sum- S^°[r ©Ethereal sulphate j 

 marises the results obtained by 5 

 Takahashi, is of much interest. 

 Takahashi was mainly inter- 

 ested in the ethereal sulphates 

 as an index of the capabilities 

 of the embryo for detoxicating 

 substances harmful to it. As 

 Fig. 399 shows, the total sul- 

 phates in milligrams per cent, 

 increase considerably in the 

 allantoic liquid from the 9th 

 day onwards, and this increase 

 is shared equally by the in- 

 organic and ethereal sulphates. 

 It is puzzling that Takahashi 



Days -»- 5 



Fig- 399- 



found a good deal of total sulphate on the 9th day in the allantoic 

 liquid, but almost no inorganic sulphate, so that, as the difference was 

 taken to be the ethereal sulphate, there was much more of the latter on 

 the 9th than on the 1 2th day. Takahashi himself seems to have thought 

 that something was wrong with these figures. However, the main 

 outlines of what is happening stand out clearly, for in the embryo 

 itself the total sulphate remains constant, as do its two components, 

 except for the preHminary irregularities which are associated with 

 that just mentioned. Takahashi's conclusion was that ethereal 

 sulphate as a mode of excretion is already in action by half-way 

 through development. But where does the phenol so excreted 

 come from? At that stage there are no bacteria in the gut of the 

 embryo nor would there be much for them to act upon even if they 

 were there. 



