In order to measure the physiological activity of domestic animals under conditions of least restraint and stress, a miniaturized FM/FM radio transmitter was built. Tow different types of transmission system were made. The transmitter, with battery, weighed 27g and had a dimension of 32×60×11 mm. The characteristics of one transmitter (type II) were: input impedance=45KΩ, voltage gain=70db (2Hz-1KHz), minimum sensitivity=50μV, time constant=0.1 sec, carrier frequency=76-90 MHz, frequency deviation=20 KHz, battery=1.3 volts mercury cell (H-D) and continuous for about 100 hours, current consumption=0.95mA (under loading), and distance=20-30 m. Those of the other transmitter (type III) were: input impedance=500KΩ, voltage gain=65db (0.5-100 Hz), and time constant=1.5sec.
In a dairy cow, radio maternal ECG recorded with the type II transmitter by A-B lead showed a distortion on each wave, compared with that by routine A-B lead. Recorded with the type III transmitter, radio maternal ECG showed a similar pattern in P, QRS, and T waves and a slight degree of distortion in the ST segment, as compared with the routine ECG. From a horse the same results as these were obtained.
The activities of biting and tail movement were also recorded as a surface EMG with the type II transmitter. In the course of rumination, with electrodes placed on the M. masseter and the upper portion of the M. cleidooccipitalis, the surface EMG signals of redeglutition, regurgitation, and remastication were also recorded. In the remastication, a very regular burst of EMG was observed, as compared with the pattern of biting of green grass or hey. The movement of the tail in the cow could be recorded as a high-amplitude EMG burst which corresponded to each wag of the tail.
In the observation of the physiological activities in free cows against the attack of insects (mainly Tabanus) in the summer season, the radio maternal ECG and surface EMG of biting and tail movement were recorded simultaneously during about 10 hours with the type II transmitter at the distance of 30m. When the cow was protected from the attack of insects in a net room, a decrease in heart rate, prolongation of feeding time, frequent remastication, prolongation of sitting time, and no movement of the tail were observed, as compared with the cow held under exposure to insects.
From the above-mentioned experiments, the newly developed miniaturized transmitters were recognizedto be useful for obtaining some bio-physiological data in free cows as a multi-biotelemetry system.

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In order to obtain electrocardiograms of the horse during exercise, regardless of the location of the horse, a portable electrocardiograph was tentatively manufactured. It was small in size and equipped with a magnetic tape recording system.
In the application of this system to electrocardiographic examination of the horse during exercise, it was found that the apparatus was useful for observation of the heart rate during exercise and of ventricular arrhythmia, although there were a slight distortion of electrocardiogram and unfavourable noises interfering with tracing. Causes of these distortion and noises were discussed. Furthermore, in the application of this apparatus to clinical examination, a case was encountered which revealed the paroxism of a short run of venticular flutter in its electrocardiograms during exercise, although there were no abnormalities in the electrocardiograms at rest.

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The authors observed phonocardiograms (PCG's) with the advance in growth of 4 calves under fattening. PCG's were recorded 8 times at intervals of 2 weeks for 98 days extending from 116 to 259 days after birth. The site of recording was the mitral valve area on the body surface. They were analyzed for the following factors: pattern of PCG, duration of the first (S₁), second (S₂), and foruth (S₄) heart sound, Q-S₁, Q-S₂, and P-S₄ interval, amplitude ratio (S₂/S₁, S₄/S₁), and frequency of S₁, S₂, and S₄ heart sound. The results obtained are summarized as follows.
1. The patterns of S₁ and S₂ were a crescendo-decrescendo type in all the calves examined in both L and M₁ filter recordings.
2. The duration of S₁ and S₂ in all the calves was calculated to be 0.12-0.14 and 0.06-0.07 seconds, respectively, during the observed period of fattening process in both filter recordings.
3. The Q-S₁ interval in all the calves was calculated to be 0.03-0.04 seconds in both filter recordings.
4. The Q-S₂ interval in all the calves was calculated to be 0.33 seconds over a period from 161 to 203 days after birth. It began to prolong, however, to 0.35 seconds at 216 days of age in both filter recordings.
5. The amplitude ratio (S₂/S₁) in all the calves ranged from 0.3 to 0.6 in both filter recordings.
6. In all the calves an atrial sound was frequently recorded over the period of observation. The pattern, frequency, duration, P-S₄ interval, and S₄/S₁ ratio were the crescend-decrescend type, 20-50Hz, 0.04-0.09 seconds, 0.07-0.13 seconds, and 0.2-0.6, respectively.
The PCG of calves indicated no characteristic changes with the advance in growth because of the short period of observation.

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Electrocardiograms were recorded in 17 female Rhesus monkeys 4-7 years old weighing 3.5-7.5 kg by the unipolar lead from the thoracic area on the body surface. Distributions of wave forms and potentials of the QRS complex were discussed electrocardiographically on the basis of the relative position of the heart in the thoracic cavity.
1. The minus and the plus pole of the QRS complex which had been calculated from unipolar electrocardiograms were placed in the right frontal and the left rear part of the thorax respectively. A transitional zone was described obliquely from the left axilla to the lower right part of the thorax. The pattern of the QRS complex showed the rS or QS type on the minus zone and the Rs or qR type on the plus zone.
2. The position of the electrode in A-B lead speculated from unipolar electrocardiograms was the same as reported by Uchino et al. in Macaca fuscata. It was also considered to be suitable for the anatomical observation of the heart in the thoracic cavity.
3. Six unipolar lead positions were indicated from the results obtained on the relationship between the positions of both nipples and ventricles. It was assumed that the above-mentioned lead method might be applicable at least to Macaca monkeys.

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