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T H E studies on the response of the fetus in utero to vasoactive drugs have centered around two main questions. The first question has been concerned with the changes in the fetal circulation when these agents are injected into the mother. Some author? have observed fetal bradycardia and hypotension after the administration of catecholamines to the mother and have attributed these to fetal asphyxia resulting from the uterine ischemia caused by these agents. Adams and associates,2 however, were unable to detect any circulatory alterations in the fetal lamb after the injection of single doses of catecholamines or angiotensin into the ewe. Neither were they able to note any alterations in the ewe when the same agents were injected into the fetus. These authors concluded that these vasoactive drugs either did not cross the placental bar

A laboratory investigation was conducted on oil displacement from porous media by the use of either a slug of propane followed by gas or a slug of carbon dioxide followed by water. A comparison was made of the efficiencies of these two solvent flooding processes for petroleum reservoirs. The results of flooding experiments on cores and on scaled pattern models showed the effect, on oil recovery, of type of porous medium, pore geometry, length to width ratio of the flood pattern, fluid viscosities, and miscibility. Oil recoveries of from 60 to 80% of the original oil in place were obtained by these solvent flooding processes as compared with conventional waterflood recoveries of between 35 to 50% on the same cores and linear models. Furthermore these recoveries were obtained with solvent slug sizes of 10 to 30% of a hydrocarbon pore volume, with less solvent being required as the length of the flood path increased. Data showing the relations between mobility ratio and volumetric sweep efficiency for the propane-gas and carbon dioxide water flooding processes for two widely different types of porous medium are included in this paper. It was concluded that in reservoirs where pressure, oil viscosity and composition, and flooding pattern are favorable, either of these solvent flooding processes would give oil recoveries considerably higher than conventional waterflood or gas drive. It was further concluded that this improved recovery would be realized earlier in the life of a flood with carbon dioxide-carbonated water than with propane followed by gas.

The acid-base status of the fetal lamb was studied in near-term pregnant ewes subjected to spinal anesthesia. The status of the fetus was compared to its mother and the changes which occur after the fetal lungs were ventilated with oxygen or nitrogen were investigated. The results show that: 1) the fetus in utero is in a state of metabolic acidosis in relation to the mother, 2) the acidosis does not seem to be related to the fetal blood pCO2, and 3) the acidosis may be aggravated by hypoxia. fetal acidosis; blood pH; blood oxygen; blood carbon dioxide; hypoxia; hyperoxia; sheep Submitted on March 20, 1963

The metabolism of free fatty acids (FFA) was studied in the term ewe, sheep fetus and newborn lamb. The concentration of FFA is about 10 times greater and the concentration of triglyceride fatty acids (TGFA) 2 1/2 times greater in maternal than in fetal plasma. After intravascular administration of palmitic acid-1-C14 complexed to homologous albumin, the initial rates of disappearance of FFA radioactivity from maternal and fetal circulations were similar, with half-times of approximately 2 minutes. Radioactivity appeared in the opposite circulation as FFA indicating that the syndesmochorial placenta is permeable to palmitic acid. Survival of the newborn lamb is associated with a fivefold increase in plasma concentration of FFA and no significant change in glucose or fructose during the first 30 minutes after birth. Failure to survive is associated with lack of increase in plasma FFA concentrations, while glucose concentrations do not differ from those found in surviving lambs. These data suggest that sympathetic nervous system activity is responsible for the FFA elevation and that increased activity of the sympathetic nervous system or FFA mobilization is closely related to survival of the newborn lamb.

SUMMARY Complete bilateral removal of the adrenal glands of sheep foetuses in utero resulted in failure of the ewes to undergo labour. Thirty-seven ewes with dated pregnancies were operated on approximately 1 month before term. Eight foetuses were carried in utero past term; all showed definite signs of postmaturity.

The effects of hypoxia (administration of 10 per cent O 2 in N 2 and constriction of the uterine arteries), of hypercapnia (administration of 8 per cent CO 2 in air), and of asphyxia (obstruction of the umbilical circulation) were studied on the fetus in utero in near-term pregnant ewes under spinal anesthesia. Hypoxia and hypercapnia produced increases in the maternal arterial pressure, maternal heart rate, and uterine blood flow. Fetal arterial pressure and carotid and umbilical blood flows increased, while the fetal heart rate decreased. Fetal femoral flow decreased during hypoxia and increased during hypercapnia. There was a delay of five to six minutes between the initiation of hypoxia or hypercapnia and the appearance of fetal circulatory changes. Transient reduction of uterine blood flow evoked insignificant hemodynamic alterations in the mother and fetus. A reduction of flow greater than 50 per cent of control values produced a fetal bradycardia along with increases in fetal arterial pressure, carotid and umbilical flows. Constriction of the umbilical veins with the umbilical arteries intact produced a prompt bradycardia together with a decrease in fetal arterial pressure and regional blood flows. Constriction of the umbilical arteries alone also produced a bradycardia with an initial rise in arterial pressure and carotid flow. Similar changes were observed after cutting the umbilical cord. Elimination of the low resistance of the placenta played a major role in these changes. Placing the lamb in the head-down position caused a marked increase in carotid blood flow without greatly modifying arterial pressure.

The nuclides ${\mathrm{Fm}}^{250}$, ${\mathrm{Fm}}^{251}$, and ${\mathrm{Fm}}^{252}$ were produced by alpha bombardment of ${\mathrm{Cf}}^{249}$. The excitation functions for their formation, as well as some of their nuclear properties, were measured.

The new isotope ${\mathrm{E}}^{248}$ has been identified among the products of the deuteron bombardment of ${\mathrm{Cf}}^{249}$. It decays principally by electron capture with a half-life of 25\ifmmode\pm\else\textpm\fi{}5 minutes and also by the emission of (6.87\ifmmode\pm\else\textpm\fi{}0.02)-Mev alpha particles. A branching ratio ($\frac{\mathrm{E}.\mathrm{C}.}{\ensuremath{\alpha}}$) of \ensuremath{\sim}400 was determined from the amount of ${\mathrm{Cf}}^{248}$ formed by electron-capture decay of the new isotope. Partial excitation functions supporting the assignment to mass number 248 are presented.