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SUMMARY.— Thymidine uptake studies using a predominantly lymphocyte suspension of white blood cells in a series of 12 cases of nickel contact dermatitis and 14 controls are reported. In none of the controls was there any evidence of significant thymidine uptake. In 7 out of the 12 nickel hypersensitive subjects there was significant 14C thymidine uptake when the lymphocytes were stimulated by a concentration of nickel of 10–4 mEq/ml. culture. Possible explanations for failure of transformation in the other 5 subjects are discussed.

Proton magnetic resonance spectroscopy of solutions obtained by treatment of dimethyl-and diphenyl-zinc with ethanol, propan-2-01. and 2-methylpropan-2-01 show that the monoethanolysis products are similar to the monomethanolysis ones described previously, but that the other alcohols yield simpler systems which are probably composed almost exclusively of aggregates of true organozinc alkoxides RZnOR'. The products from reactions with 2-methoxyethanol can also be formulated as true organozinc alkoxides, back co-ordination from the methoxyl oxygen atom to the zinc probably accounting for this difference from the ethoxide systems.The methylzinc n-dodecoxides and t-butoxides differ from the other systems in that the materials formed by treating the preformed zinc alkoxide with dimethylzinc are spectroscopically different from those obtained by direct monoalcoholysis.