. Chemical embryology. Embryology. 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°'^' '"'.
. Chemical embryology. Embryology. 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 12th 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
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Keywords: ., bookcentury1900, bookpublishernewyorkthem, booksubjectembryology
