1. ECGs traced on the ventral surface of the chest case were superimposed in a chart and deflection amplitudes were compared to each other to determine appropriate sites of the electrodes.
2. On the basis of results obtained, a negative electrode was placed on the Manubrium Sterni and a positive one on the Sternum close to the apex of the heart.
3. Transmitter subcutaneously implanted on the breast bone was pertinent for reducing the length of lead wire and minimizing the external noise.
4. Successive ECG tracings after dosage with Digitoxin and Quinidine were illustrated to show the possibility of miniaturized transmitter K6 in clinical use.

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In 6 cases of pregnant cows with different fetal ages and a case of pregnant mare, chloral hydrate was given by slow injection intravenously for obtain a light anesthesia to surgical operation. Four cows and the mare were presented for clinical observations on pregnancy, parturition and newborns' condition. In other cases, maternal and fetal electrocardiographical observations were performed during administration of chloral hydrate, -during anesthetic state and after operation. Several considerations of effect of the drug on pregnancy especially to fetal condition were made. The results obtained are as follows.
1) In 4 cases of Holstein cows with fetal ages of 60 days (No. 1), 131 days (No. 2), 210 days (No. 3) and 270 days (No. 4) respectively, 60g (No. 1), 70g (No. 2), 50g (No. 3) and 35g (No. 4) of chloral hydrate as 5 percent solution were administered intravenously for surgical operation. Except case No. 3, 3 cows showed normal pregnant course and calved normally with good parturition. In case No. 3, at 270 days gestation, she was slaughtered by an accident of the femoral bone fracture. Condition of gestation and fetus showed completely normal.
In a mare of Thoroughbred breed with 150 days gestation, 45g of chloral hydrate was given by the route of jugular vein for operation of tenosuture. The case had normal gestation period and had normal foal with natural parturition.
2) Two Holstein cows with fetal age of 176 days and 192 days were presented for maternal and fetal electrocardiographical examination during anesthesia by injection of chloral hydrate. Fetal ECG was obtained by a method of bipolar lead from surface of maternal abdominal wall. Maternal ECG was recorded by telemetering from apex-base lead. Maternal heart rate in both cases showed gradual increase just after beginning of the administration. A higher level of maternal heart rate compared with value of before injection was maintained during operation. Fetal heart rate in both cases showed a slight increase during operation. This higher rate of fetal heart rhythm returned to before value at maternal awake.
Maternal electrocardiograms showed a decrease of TP interval and higher amplitude of T wave caused by a increase of heart rate. In case No. 7, slight degree of ST deviation was recorded during anesthesia. No fetal and maternal arrhythmia and fetal bradycardia were seen. The cows had normal calves with natural parturition.

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[in Japanese]

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