In recent years, it has become apparent that lesions of the suprarenal glands occur more often in human disease than had formerly been suspected. The evident effect of such lesions is the production of profound general disturbances, which are seen in a chronic phase if the morbid process in the suprarenal tissue is slowly progressive, as, for example, in the ordinary case of Addison's disease, and in an acute phase if the lesion is of sudden onset, as in suprarenal haemorrhage, or if chronically diseased suprarenal tissue is subjected to sudden excessive demands, as in the critical stage of Addison's disease. In both phases, there is evidence to show that the best measures to employ in combating these disturbances, whether for prophylaxis or for therapy, consist of the administration to the patient of an extract of suprarenal cortex or, alternatively, of sodium chloride.

From results obtained from the twenty-two patients with essential hypertensions we find that their CO2 and O2 subcutaneous tissue gas tensions lie within normal limits. Thus (1) there can be no thickening of the capillary walls, and (2) the blood flow through the capillaries is normal.

During the last few years a considerable amount of experimental evidence has accumulated which indicates the importance of chemical structure in determining the specificity of both natural and synthetic antigens. This work has been summarized by Marrack (1934), Landsteiner (1936) and Morgan (1936), and it is therefore not proposed to discuss in detail the investigations which have contributed to our present-day conception of this aspect of immunity reactions. Contributions which seem essential for understanding the ideas developed in this communication will, however, receive mention.

The designation, Newington, is proposed for those cultures of S. anatum having the antigenic formula III XV: eh: 1, 4, 6. A new type, New Brunswick, is described which is represented by the formula III XV: lv: 1, 7 +. Attention is called to the inadequacy of the symbols currently employed in the representation of the non-specific antigens to express correctly the non-specific phases of the Nyborg and New Brunswick types.

Although attempts to produce an active immunity against diphtheria were made as early as 1902, it is since the Schick test was described in 1913 that there has been available some clinically applicable measurement of individual immunity, naturally obtained or artificially produced; and it is probably true to say that large-scale active immunization has been practised in this country for only some 10 or 15 years.

The observations described in this paper were carried out as a preliminary to a systematic study of the influence of dietetic factors on resistance to infection. The enquiry was initiated under the general direction of Prof. W. W. C. Topley of this School, and Prof. E. P. Cathcart of the University of Glasgow, and has been financed by a grant from the Medical Research Council. It was desired that all aspects of the problem, dietetic, immunological and statistical, should receive full and careful consideration at each stage of the investigation, and that any significant results, positive or negative, should be checked and controlled on a scale that would supply a firm foundation for further studies. To this end, a small advisory committee was formed, soon after the enquiry started, on which Prof. M. Greenwood, Prof. J. C. Drummond, Prof. Edward Mellanby, Dr Harriette Chick, Dr Bradford Hill and Dr Joyce Wilson kindly consented to serve. To all the above, I wish to express my thanks for help and advice. I wish also to acknowledge my indebtedness to Miss J. M. Hatswell for her assistance throughout the greater part of this work.

The preceding paper recorded experiments on the influence of various “natural” and “synthetic” diets on the fertility of breeding does, and on the growth and survival of young mice. The present paper records the relative resistance of mice, bred and reared or fed for shorter periods on these diets, to Bact. typhi-murium, or to its endotoxin.

1. By means of a new technique, using the “closed bowl” of the Sharpies-Super Centrifuge, in which the distance which the virus particles have to travel under the influence of a given centrifugal force until they are caught mechanically in an agar-gel lining the wall of the bowl amounts to only a few tenths of a millimetre, the potency of 5 c.c. of a foot-and-mouth disease virus suspension can be reduced by 90–99 per cent in 3 min. using a centrifugal force of 24,000 times gravity. The virus can be recovered without loss by extraction of the agar-gel either in fresh medium or even in the liquid layer or “supernatant”, thus showing that adsorption phenomena play no role whatever in the effects obtained by centrifugation.

2. The non-adsorbability of the virus by the agar, however, is determined by the presence of a certain though very small amount of impurities presumably protein which seem to have a “protective” effect. The limit of nonadsorption of the virus by the gel appears to be in that region of “purity” where the sulphosalicylic acid test for protein is negative whereas serological precipitation reactions for host protein are still positive. Virus purified beyond this limit is strongly adsorbed by an agar-gel.

3. Measurements of the sedimentation rate were made on three strains of virus of different type Vallee A, Vallee 0 and Waldmann C and no differences between the three strains were observed. The average diameter of the virus particles determined from the sedimentation rate data was 20 mμ. All the evidence now available for the monodispersity of the virus is discussed. The fact that the infective particles are uniform in size indicates that the measurements recorded here concern actually the single virus elements.

4. The sedimentation equilibrium of the virus has been estimated. The value calculated on this basis for the weight of a single virus particle is circ. 1 × 10−17 g. The diameter of a sphere of this weight and density 1·30 would be 25 mμ. The size values for the virus, 25 mμ estimated from sedimentation equilibrium data and 20 mμ estimated from sedimentation rate data, are discussed in relation to the possible shape of the virus particles.

5. The virus can be sedimented in sucrose and sucrose-salt solutions of densities up to 1·28. On the basis of the sedimentation rates in these media the specific gravity of the virus particles is estimated to be about 1·40. This value however may be abnormally high due to the dehydrating effect of the high concentration of salt or sugar. The application of the centrifuge technique described here to the concentration and purification of the virus of foot-andmouth disease in conjunction with ultrafiltration methods will be the subject of a second paper by Galloway & Schlesinger (1937).

1. It is possible to concentrate the virus of foot-and-mouth disease on filter candles coated with acetic acid collodion. The degree of concentration of the virus effected was to the limit of expectancy, i.e. the increase in titre after concentration corresponded to the reduction of the volume of the liquid.

2. By a combination of the two methods of purification of the virus, viz. washing once in the closed agar-lined cylinder of the Sharpies-Super Centrifuge and repeatedly on a graded collodion membrane of A.P.D. 25 mμ, very potent purified concentrates of virus can be rapidly obtained, especially if the final concentration is made on filter candles, coated with acetic acid collodion. In this way a concentrate of virus with a titre of 10−8 and a negative sulphosalicylic acid test for protein has been prepared in one day from virulent vesicle lymph (diluted 1 : 2) having a titre of 10−6.

3. The possibilities of the different methods of purification and concentration of the virus are discussed and a scheme suggested for their application.

In earlier papers (Gordon, 1930) it was shown that congo red has an inactivating effect on serum complement, both haemolytic and bactericidal, and that this effect can be reversed by treating the serum and congo red mixture with charcoal, the charcoal removing the congo red and leaving the complement active again. A similar reversal of inactivation is obtained by using instead of the charcoal, heated serum (55° C. for 30 min.) or protein solutions. Later (Gordon, 1931), it was shown that congo red had an inactivating effect on the haemolysins of Streptococcus haemolyticus and B. welchii. The reversibility of this effect was not so easy to demonstrate as with complement. Charcoal had a destructive effect on the haemolysins and so could not be used. It was found, however, that when the concentration of congo red was just sufficient to neutralize the streptococcal haemolysin, the addition of cuprammonium artificial silk adsorbed the congo red and liberated the haemolysin. In the case of B. welchii this method of reversal was not suitable, as the artificial silk had a destructive effect on the haemolysin. Instead, reversibility was demonstrated by adding ox serum to the mixture of congo red and haemolysin. This brought about a redistribution of the congo red between the ox serum and the haemolysin and if the amount of congo red used had been only just sufficient to neutralize the haemolysin of B. welchii, then the haemolytic activity could again be demonstrated. Gordon and Robson (1933) showed that congo red interfered with the anaphylactic reaction tested both in vivo and in vitro, the guinea-pig uterus being used in the in vitro experiments, in which the inhibitory action of the dye was shown to be reversible. It was suggested that the congo red interfered with the entrance of antigen into the cell.

1. All tests of spermicidal power are done with human semen at 37° C.

2. The total spermicidal power of pure substances and commercial products is measured by a test which is not intended to represent natural conditions very closely, but which gives consistently reliable results. The activity of the sperms is determined at 5 and at 30 min.

3. A commercial product of high total spermicidal power may be useless on account of the slow rate of diffusion of the spermicide out of the vehicle. A special test measures the rate of diffusion. This test is designed to represent natural conditions as well as is possible in the laboratory. The test is made as stringent as possible by avoiding mechanical mixture of the product with the semen. The activity of the sperms is determined at 2, 5, 15, 30, 60, 120, and 180 min.

4. The rate of disintegration and acidity or alkalinity of commercial products is measured.

5. The pathological test consists in inserting one-half the prescribed dose of a commercial product into the vagina of a bitch daily (except Sundays) for a fortnight, and then sectioning the vagina and examining microscopically.

6. A method is described whereby the pH of human semen may be determined colorimetrically rather accurately.

7. The average ejaculate of the human semen we have studied, from 13 donors, measures 3·9 c.c, contains 461 million sperms, and requires 3·1 c.c. of N/100 HCl to neutralize it.