Porter's numbering system has been retained: the first figure is a running number and the second figure represents the year. The first 18 slides in the box are group A, and the last 9 are group B.

18 Group A slides, including:

(530-531/59) E.M. Press, R.R. Porter and J. Cebra, 'The isolation and properties of a proteolytic enzyme, cathepsin D, from bovine spleen' (Bibliog. 16); research on proteolytic activity in bovine spleen to determine the fate of antibodies in an antibody-forming organ, which led to the discovery of the enzyme cathepsin D; two of fifteen slides [previous 13 slides are in MS. Photogr. e. 67], comprising:

(287/60) 'Inhibition of precipitation with anti-HSA digest', fig. 2 in R.R. Porter, 'Separation and isolation of fractions of rabbit γ-globulin containing the antibody and antigenic combining sites' (Bibliog. 14). Precipitation of human serum albumin (HSA) by rabbit antibody to HSA is inhibited by a papain digest of the antibody. The digest has no effect on the equivalent bovine albumin system.

(328/60) 'Transmission of γ-globulin and antitoxin across the 24 day foetal yolk-sac membrane', simplified version of table 2 in F.W. Brambell, W.A. Hemmings, C.L. Oakley and R.R. Porter, 'The relative transmission of the fractions of papain hydrolyzed homologous γ-globulin from the uterine cavity to the foetal circulation in the rabbit' (Bibliog 17). Slide shows extent of the transmission of γ-globulin and fractions across the rabbit foetal yolk-sac membrane. This is the original evidence that placental transfer of antibody molecules is dictated by the Fc component. Fab fragments are not transferred. Pepsin digestion removes Fc leaving a double Fab fragment.

(329/60) 'Sedimentation coefficient after peptic digestion', in the presence of cysteine there is further breakdown of the double Fab to single Fab fragments.

(330/60) 'Distribution of properties of antibody fractions', the different properties of Fab and Fc fragments of γ-globulin

(NY-1-2) R.R. Porter, 'A chemical study of rabbit antiovalbumin' (Bibliog. 2); two slides, [c.1950], comprising:

(NY-3-5) R.R. Porter, 'The formation of a specific inhibitor by hydrolysis of rabbit antiovalbumin' (Bibliog. 3); three slides, [c.1950], representing early evidence that one can separate the binding site from other parts of the antibody molecule [see slide 24/59 above], comprising:

(NY-6-10) early experiments investigating the reactivity of lysine ε-NH 2 groups in various proteins with fluorodinitrobenzene. Probably from Porter's PhD thesis, 'The free amino groups of proteins' (Cambridge University, 1948). Horse pseudoglobulin presumably refers to that fraction of horse serum prepared as for bovine globulin. Five slides, comprising:

(NY-11) 'Table 9. The specific action of antihaemoglobin serums', species specificity of antibodies to haemoglobin, probably made in rabbits. Results taken from L. Hetkoen and A.K. Boor who were publishing in the 1930s.

(NY-12) 'Crystalline fraction III x 1150', crystals of Fc [see slide 24/59 above]

9 group B slides, including:

(112/50) N-terminal amino acids and reactive lysine determination using fluorodinitrobenzene

(113/50) 'The numbers of free amino groups of haemoglobins', N-terminal amino acids and numbers of lysines in haemoglobins of different species

(259-262/51) H. Fraenkel-Conrat and R.R. Porter, 'The terminal amino groups of conalbumin, ovomucoid and avidin' (Bibliog. 5), a study of N-terminal amino acids and lysine numbers in conalbumin, ovomucoid and avidin; four slides, comprising:

(210/52 and 212/52) R.R. Porter, 'Partition chromatography of insulin and other proteins' (Bibliog. 6); partition chromatography of different preparations of crude insulin; two slides, comprising:

(433/52) 'Chymotrypsin activated by trypsin', separation of chymotrypsin from chymotrypsinogen; method not identified but apparently not partition chromatography [compare Bibliog. 10, fig. 9]