Batches Of Embryos Research Articles

REPRODUCTIVE BIOLOGY OF LYCHAS TRICARINATUS (SIMON)

1. An unusual instance of embryonic diapause in a scorpion is described. Among the eggs that are fertilised at a time, only a few sink into the ovarian tube and continue to develop to maturity while the others remain in a state of arrested growth or diapause, until the extrusion of the first batch of embryos. Further insinking of the eggs appears to be prevented by the secretion of corpus luteum 1.2. After the extrusion of the first batch of embryos the diapausing embryos get revived and sink into the ovarian tube to give rise to the next brood. The termination of the diapause. also, appears to be in response to a secretion from another glandular structure, termed here corpus luteum 3. This incidentally explains how Lychas can produce two or three broods in succession without undergoing repeated copulation.

A STUDY OF CONDITIONS FOR THE OPTIMUM PRODUCTION OF PR8 INFLUENZA VIRUS IN CHICK EMBRYOS

In order to determine the conditions for the optimum production of PR8 influenza virus in chick embryos, a study has been made of the róles of concentration of virus in the inoculum, temperature of incubation of infected embryos, length of time of incubation of infected embryos, and age of embryos at the time of inoculation. Relative amounts of virus in different preparations were measured indirectly by means of determinations of chicken red blood cell agglutination titers. Frozen infectious allantoic fluid which produced infection in chick embryos at a maximum dilution of 10(-7) was employed as a stock inoculum. Best results were obtained with an amount of stock inoculum of 0.1 cc. of a 10(-5) dilution, a temperature of incubation of 35 degrees C., a length of time of incubation of 36 to 48 hours, and with embryos brought to 10 or 11 days of age at 37 degrees C. or 9 or 10 days of age at 39 degrees . An uncontrolled factor arising from inherent variations in the properties of different embryos and different batches of embryos was discussed.