The investigation was undertaken to compare the blood supply and venous drainage of the brain of the baboon P. ursinus, the vervet monkey C. pygerithrus, and the bushbaby G. senegalensis with that of man, because these animals are extensively used as research models. The blood supply of the three primates was found to be similar in each case. Like man they have a complete circulus arteriosus; but they have a single anterior cerebral artery, whereas man has paired anterior cerebral arteries. The arterial supply to the cerebellum in the primates is similar to that in man, the main difference being a "common inferior cerebellar artery" which bifurcates to form the anterior inferior cerebellar and posterior inferior cerebellar arteries. In man, these arteries arise separately from the basilar artery and vertebral arteries, respectively. The dural venous drainage was also found to be similar in these primates but was far more extensive than in man. The primates have additional sinuses--the more important of these being the "basisphenoid sinus" and the petrosquamous sinus. The former drains the basilar sinus and is itself drained via the vertebral venous plexus and internal jugular vein. The latter drains via the petrosquamous foramen into the retromandibular vein. The petrosquamous sinus has a rostral extension which drains through the foramen ovale and two lateral and medial connecting sinuses which drain the cavernous and basilar sinuses, respectively. These sinuses are not found in man.

A study of the microvasculature of the omentum using corrosion casts was undertaken. The object was to supply information regarding the morphology of the three-dimensional structure of the microvasculature information which may be valuable in understanding the functions of the omentum. Corrosion casts of rat omenta were prepared and studied. Characteristic glomerular-like capillary beds were identified. Some of these beds were densely and others loosely arranged. Two types of capillaries made up these beds, tortuous and straight capillaries. These beds also showed a planate surface giving the impression that they lie directly under the mesothelium.

The ‘anatotopography of cranial thoracic inlets, the carotid body and associated structures in the caudal pole of the thyroid gland are described. The source from which the various groups of fowls (n = 65) were obtained as well as the varied localisation of the carotid body are indicated. In this investigation, the carotid body was found to be situated mostly (49 cases) either on or in the immediate vicinity of blood vessels (carotid and inferior thyroid artery) and only in 14 cases in close association with the parathyroids.

The histotopography of the silvery-white glistening carotid body and the branchial derivates in the cranial thoracic inlets as well as the histocytology of the particular organ were revealed by various microtechniques. Three types of randomly distributed epithelioid cells, many capillaries, and small and large sinuses are observable. Myelinated fibres are sparsely distributed. 25 clinically healthy white leghorn males were used for this investigation.

Sterba’s technique to detect neurosecretory substances was applied to carotid body tissue, surrounding branchial derivatives, ganglion nodosum and the carotid arterial wall. Mainly a yellowish-green, a yellowish-red and a bright yellow fluorescence was observed as well as greenish-yellow fibres with varicosities and terminal knobs. The metachromatic reaction of the technique was briefly discussed.