蚕児

PART I : So called liquid-silk which is a colloidal silk solution in the silk glands of Bombyx mori has negative electric charge and is readily coagulated by the addition of some acid. For the purpose to determine the effect of hydrogen ion concentration upon the liquid-silk acetic, hydrochloric, lactic, phosphoric and oxalic acids were used. The optimum coagulation-point were PH 1.3 and 3.9. The later point is very near to the isoelectric point of sericin. : PART II : Cystine content in the proteins of silk worms and pupa was determined by OKUDA'S iodine method. The content in the total body protein or in total dry matter decreased gradually during the development of the worms or in the course of silk formation, as silk contains very little cystine. After spinning the cocoon or the excretion of silk, most of the cystine remains in pupa. Tryptophane content was determined by the colorimetric metho d of MAY and ROSE, and its quantitative changes was found to be somewhat similar with that of cystine. Tyrosine c ontent in the total body protein which was determined by the method of FOLIN and DENIS, on the contrary, increased accompanied with the silk formation, as silk is rich in tyrosine.