1. The activity of single myelinated fibres innervating mechanosensitive units in the dorsal skin of the ears of New Zealand White and Chinchilla rabbits has been recorded with glass micropipette electrodes, inserted into intact bundles of the great auricular nerve.2. Only two types of afferent unit were observed: hair units, sensitive to hair displacement, and skin spot units, sensitive to deformation of spot-like areas of skin between the hair orifices. Hair units were more numerous and no unit contained receptors of both types. Up to nine hairs or six skin spots composed each hair or skin spot unit, respectively. Both types were rapidly adapting.3. The areas of the receptive fields of the hair units were significantly larger in the New Zealand White than in the Chinchilla strain.4. In the hair units from the Chinchilla rabbits: (a) there was no correlation between the receptive field areas and the conduction velocities of the afferent fibres; (b) the areas and conduction velocities of the units showed no significant topographical distribution over the ear; (c) the extent of the overlap of the receptive fields was estimated and the sum of the areas is shown to be about 40 times the area of the ear.

Action Potentials↗

PubMed1966

Evaluation of slit sampler in quantitative studies of bacterial aerosols.

Quantitative studies were conducted to evaluate the efficiency of the slit sampler in collecting airborne Serratia marcescens and Bacillus subtilis var. niger, and to compare it with the collecting efficiency of the all-glass impinger AGI-30. The slit sampler was approximately 50% less efficient than the AGI-30. This ratio remained the same whether liquid or dry cultures were disseminated when the sample was taken at 2 min of aerosol cloud life. At 30 min of aerosol cloud life, this ratio was approximately 30% for B. subtilis var. niger. S. marcescens recoveries by the slit sampler were, however, only 17% lower than the AGI-30 at 30 min of cloud age, indicating a possible interaction involving the more labile vegetative cells, aerosol age, and method of collection.

Aerosols↗

PubMed1966

Quantitative assay of Coxiella burnetii in mice.

Experimental data are presented which demonstrate that the complement-fixing antibody response in individual mice can be used for quantitative assay of Coxiella burnetii. The method allows the replacement of a single guinea pig with a single mouse, thus resulting in considerable savings in caging requirements and animal costs.

Animals↗

PubMed1966