352 THE UNFERTILISED EGG AS A [pt. iii 



in those of Asterias, and more lecithin in the eggs of Asterias than 

 in those of Arbacia. Asterias contains large amounts of soaps, and 

 its oil is present in much greater abundance than the oil of 

 Arbacia; moreover, it contains more sulphur compounds (sul- 

 phatides?) decomposable with potash than does the Arbacia egg. 

 Page, Chambers & Clowes made a study of the effects of various 

 cytolytic agents on the eggs of Asterias separated by microdissection 

 into their cortical and endoplasmic components. They used for this 

 purpose hypotonic sea water, digitonin and saponin, and found that 

 digitonin caused slow cytolysis of the cortical and rapid cytolysis of 

 the interior protoplasm when the two were isolated, whereas hypo- 

 tonic sea water caused slow cytolysis of the interior and rapid 

 cytolysis of the cortical protoplasm. If these results do not actually 

 demonstrate that the greater part of the asteriasterol is localised in 

 the outer and fertilisable parts of the egg, they at any rate suggest 

 a new method of investigation which may help to solve many similar 

 questions in the future. Runnstrom has studied the lipoids of the 

 echinoderm Qgg in relation to its coloured interference fringes and 

 its membrane properties. 



Among the sterols existing in eggs must be mentioned a substance 

 which has long been known to occur in the ova of Ascaris, and which 

 has been called "ascarylic acid". Faure-Fremiet identifies it with 

 the droplets or crystals described in the egg oiAscaris by van Beneden. 

 It was isolated simultaneously by Faure-Fremiet from the eggs and 

 by Flury from the whole body of the nematode ; the former worker 

 found that it accounted for 22 per cent, of the dry material. Ascarylic 

 alcohol, ascarylic acid, or, as it would probably be best to call it, 

 ascaristerol, seems to exist in the egg-protoplasm in combination 

 with palmitic, oleic, and perhaps stearic acid in ester form. Faure- 

 Fremiet & Leroux studied its properties, and proposed the pro- 

 visional formula of C32Hg404 . Its saponification number was 199, and 

 its m.p. 82°, it did not give the cholesterol colour-reactions, and its 

 molecular weight was close to 511. Flury considered it to be related 

 to oenocarpol. Acaristerol seems to be strictly confined to the eggs, 

 for even the parietal cells of the ovary and uterus do not contain it, 

 as Faure-Fremiet showed by means of histochemical tests. Nor is it 

 present in the testes and spermatozoa. It may at present be classed 

 with the sterols, like asteriasterol. Ascaris eggs also contain o-i6 per 

 cent, dry weight of ordinary cholesterol. 



