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Dorsal and ventral roots were dissected bilaterally on spinal cords of adult monkeys: six rhesus, six irus and three baboons. Measurements made were: the distance between the uppermost cord attachments of successive nerve roots (segment length); the distance between the uppermost and lowermost fila within each root (root attachment length); and the distance beween the lowermost fila of one root and the uppermost fila of the subjacent root (interroot length). Segment lengths, dorsally and ventrally, are essentially alike within each species. In rhesus the average at various levels ranges from 4½ mm in cervical and sacral to 12½ mm in lower thoracic; in irus, from 4 mm in cervical and sacral to 10 mm in lower thoracic; in the baboon, from 5½ mm in cervical and sacral to 19 mm in lower thoracic. Within each species the dorsal and ventral root attachment lengths are similar, as are the interroot lengths, except in the lower thoracic levels. There dorsal interroot lengths range up to 3 mm longer than ventral. Cross sectional areas of the various levels were planimetrically determined. Within each species the largest areas are at lower cervical and lower lumbar levels. Individual segment volumes were calculated. In rhesus and irus these vary only about 60 mm3 from the largest to the smallest segment, excluding sacrocaudal levels. In baboon this difference is as much as 260 mm3.

Solutions of Parlodion stored in clear glass bottles, and subjected to the usual lighting of laboratory work tables, deteriorate progressively. Blocks of nervous tissue stained by Cajal's formula No. 6 underwent marked fading when embedded in old, light-affected Parlodion solutions. Storage of nitrocellulose, either as a solid or in solution, should be in darkness, in a dark colored bottle, for example.

In cats maintained under d-tubocurarine chloride or with high decerebration, single shock stimuli were alternately given to the exposed surfaces of crus I, culmen, simplex, and tuber vermis of the cerebellar cortex. Concurrent systematic recordings were made in the brain stem from the origin of the brachium conjunctivum all the way forward to the head of the caudate nucleus. The course of the conjunctival impulses was found to conform to the distribution of the brachium conjunctivum as described by various anatomic workers. Essentially all of the pathway crossed to the opposite side at the decussation with only small inconstant potentials seen in the issilateral red nucleus and fields of Forel. The diencephalic course was through the red nucleus, fields of Forel, nucleus centrum medianum, and then into the nucleus ventralis pars lateralis, centralis pars lateralis, and the zona incerta. The system was found to end at the rcstral pole of the nucleus ventralis pars lateralis. No confirmation was made for short latency asynaptic fibers nor for any widespread bilateral projections to the diencephalon.

Two newborn and three young adult monkeys ( Macaca mulatta ) were hemidecorticated by surgical aspiration and allowed to survive postoperatively for 15 to 31 days. The brains were perfused, sectioned transversely and stained with thionine. Resulting retrograde cell degeneration in the diencephalon and various other structures was examined microscopically and a comparison made between the newborn and adult animals. In the infant monkeys the following thalamic nuclei showed heavy cell loss: anterior dorsalis; anterior ventralis; anterior medialis (lateral two-thirds); ventralis lateralis; ventralis posterior lateralis; ventralis posterior inferior; lateralis dorsalis; lateralis posterior; reticularis; medialis dorsalis, partes parvocellularis and multiformis; pulvinaris; geniculatus lateralis dorsalis; geniculatus medialis, pars parvocellularis; and suprageniculatus. Nuclei showing partial cell loss were: anterior medialis (medial one-third); medialis dorsalis, pars densocellularis; reuniens; centralis latocellularis; alaris; centralis lateralis; paracentralis; limitans; and ventralis posterior medialis. Unaffected or only slightly affected nuclei included: ventralis anterior; medialis dorsalis, pars magnocellularis; geniculatus medialis, pars magnocellularis; centrum medianum; parafascicularis; centralis superior lateralis; and assorted midline nuclei. Thalamic degeneration in the adults was similar to the infants with the following exceptions which showed more severe cell loss in the adults: ventralis anterior; medialis dorsalis, pars magnocellularis; geniculatus medialis, pars magnocellularis; centralis lateralis; and paracentralis. Additional degeneration was present in three extrathalamic structures: the medial mamillary nucleus, which showed severe cell loss in the infants and partial cell loss in the adults; the caudal half of the nucleus of the diagonal band of Broca, which had virtually disappeared; and the ipsilateral pontine nuclei which were partially affected in the infants. No differences in extent of degeneration could be ascribed to variation in postoperative survival times.