“…In addition, it failed to inhibit the growth of the tumours significantly, the tumour diameter in C. parvum treated animals 17 days after transplantation being 10-4 (9-.611.3) while that in untreated animals was 12-9 (11-8-14.2 (Mackay, 1964) and humans (Southam, 1968) with non-lymphomatous tumours. They contrast, however, with other observations in tumour bearing anim4ls (Kamo and Ishida, 1971) and patients (Litton, Hughes and Fulthorpe, 1964; Lee, Rowley and Mackay, 1970). It is thus apparent that the effect of tumours on humoral immunity is a variable one and difficult to predict with any certainty.…”