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With the advent of antibiotics and the ease of controlling infections, the practical importance of the deep cervical fascia has been considerably reduced. Nevertheless, the knowledge of the fascial layers and spaces is often helpful to the clinician in understanding certain disease processes in the neck.

SEVERE injury to the axon produces detectable histological changes in the cell body as well as proximal and distal parts of the injured fiber. This retrograde reaction in the perikaryon is commonly known as chromatolysis or chromolysis because of the apparent decrease in basophilic material in the cytoplasm. In crush injury of the axon with preservation of the sheath (termed axonotmesis by Seddon1) regeneration of the neuron may occur in a shorter time, than after complete section of the nerve.There have been many studies of motoneurons during degeneration and regeneration,2-8 but histochemical studies of the enzymes in these neurons are few. Different authors have investigated alkaline and acid phosphatases, thiamine pyrophosphatase (TPPase), succinic dehydrogenase, and cytochrome oxidase in chromatolytic neurons9-12 but metabolic significance of these changes is not known.In the present study we have investigated a number of oxidative and hydrolytic enzymes by histochemical

INTRODUCTION Previous studies on the distribution of adenosine triphosphatase (ATPase) have been carried out mostly on paraffin sections and have resulted largely in a critical analysis of methodology rather than in an interpretation of the results. The biochemical studies by Robin and Smith18 showed significant variation in the chemical composition of different parts of the gray areas of the central nervous system, and those of Naidoo and Pratt15 yielded different results under different conditions. Although the enzymes have been studied histochemically in brain stem,6 cerebral cortex,11,15 and spinal ganglia and cerebellum,21,22 little has been done so far on the spinal cord. The present work was undertaken on cryostat sections and using the enzyme techniques currently in favor. MATERIAL AND METHOD Healthy young adult rats were killed by decapitation without anesthesia, and the pieces of spinal cord, mostly from the cervical and thoracic regions, were taken

Unidentified diffuse interstellar bands may be caused by electronic transitions of impurity ions in grains which are coupled to the lattice vibrations. The 4430 absorption band has a significantly asymmetric profile, being somewhat steeper on the red side than on the blue. This feature is a prediction of the solid state model proposed for the band.