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Some haematological and biochemical parameters were studied in guinea-pigs infected intraperitoneally with Salmonella dublin 493 at 1×106 viable cells per animal. The infected animals showed a rise in temperature within 24 h, followed by depression and loss of body weight. On the 15th day post infection, haematological studies revealed a significant increase in the total leukocyte count due to both lymphocytosis and neutrophilia, and a decrease in the total erythrocyte count and haemoglobin concentration. There was also a significantly higher mean corpuscular volume and lower mean corpuscular haemoglobin concentration, indicating a macrocytic hypochromic anaemia. The infection caused a significant increase in alanine aminotransferase activity and creatinine, blood urea nitrogen and globulin concentrations, and a decrease in albumin and triiodothyronine. There was no significant effect on serum total protein or on thyroxine, or in the activity of aspartate aminotransferase in the serum.

SUMMARY Ten calves were immunized with rough Salmonella dublin and exhibited marked cellular immune response and comparatively poor humoral response. The cell-mediated immunity was exhibited by delayed skin hypersensitivity reaction of 10·0 to 14·0 mm skin thickness at 48 h post-antigen inoculation (p. i.), leucocyte migration inhibition of 73·96%; humoral immune response 18·5 to 25·5 mm by immediate skin hypersensitivity reaction at 6 h p. i., H titres 1:400 to 1:3200 and total immunoglobulin levels of 43·0 to 65·0 mg/ml of serum, in calves three weeks post immunization. On challenge with smooth. S. dublin three weeks post immunization, calves exhibited fever, diarrhoea and excreted challenge organisms not beyond one week and became normal thereafter. The calves at the time of challenge neither had high agglutinin titres nor elevated serum immunoglobulin levels, but all of them survived. The control group of calves, besides exhibiting typical symptoms, excreted the challenge organisms until death. These observations provide evidence of a relatively predominant role of cell-mediated immunity in protection of calves against challenge.

Both humoral and cellular immune responses have been found to be operative in calves surviving smooth Salmonella dublin infection. Such calves showed rises in agglutinin titre and serum immunoglobulin as compared to uninfected controls. These calves at 3 weeks post infection showed a 3-4 fold increase of initial skin thickness at 5 h post antigen inoculation - an indication of immediate type of skin hypersensitivity reaction. The maximum increase in skin thickness of 2-3 fold was observed at 48 h post antigen inoculation - a criterion of delayed type of hypersensitivity reaction. There was a moderate increase, 28.1 per cent in the migration inhibition of peripheral leucocytes during the first week and a sharp increase, 45.7 and 66.6 per cent during the second and third week post infection, respectively. Passively immunized calves on challenge exhibited delayed clinical symptoms and mortality as compared to control animals, though the calves could not be protected against challenge. The serum immunoglobulin levels in passively immunized calves decreased moderately during the first week and markedly during the second week post challenge while in the control calves the levels dropped abruptly in the first week followed by death in both groups.

Normal coordinate analyses of N, N′ -dimethylurea and tetramethylurea were carried out employing a Urey-Bradley force field. The majority of the bands observed in the infrared spectra of alkylurea derivatives arise from mixed vibrations just as in secondary amides. Dialkylureas show evidence for the presence of rotamers with NH bonds cis and trans with respect to the carbonyl oxygen. The perturbations of the mixed vibration bands of alkylureas in charge-transfer as well as metal complexes are discussed.

All the vibrational frequencies of the (α - x) and (β - x) excited states of HCN and DCN as well as the 1Au states of C2H2 and C2D2 have been calculated. Based on the calculated frequencies, thermodynamic properties of the excited states have been evaluated.

Normal vibration analysis of the in-plane vibrations of methyl N-methylthiocarbamate, CH 3 NH(CS)OCH 3 , has been carried out employing the Urey-Bradley-Shimanouchi force field; the band assignments and force constants have been compared with those of related molecules. Rotational isomerism about the C-N bond of alkylthiocarbamates has been examined by infrared and NMR spectroscopy. Perturbations of the infrared bands of CH 3 NH(CS)OCH 3 in its complexes with iodine and metals have been briefly discussed.

Ultraviolet absorption spectra of acetone and acetone-d6 have been photographed under fairly high resolution and vibrational analyses carried out. The results indicate that the C(CO)C skeleton of the excited state of acetone is non-planar; CNDO/2 calculations also substantiate this observation.