100 YEARS AGO

In Campbell Island, south of New Zealand, the breeze-fly (Helophilus campbellicus), one of the Syrphidae, so closely resembles a blow-fly (Calliphora eudypti) that when, in 1901, I captured a specimen of the first, which is rare, I thought it was the blow-fly, which is common... Now in any other locality this resemblance could be put down to mimicry. The blow-fly is common and offensive. The breeze-fly is rare and feeds on flowers. Everything favours this explanation except that in Campbell Island there are no insect-eating birds and no lizards, and consequently mimicry would be useless.

F. W. Hutton

Accidental resemblances between insects are to be expected... With regard to Captain Hutton's special instance, however, there appear to be certain points which require consideration before accepting the conclusion that the resemblance is merely a coincidence:— (1) The possible coexistence of the two species in other localities where the resemblance has a meaning; (2) the possible change of conditions in the struggle for life in the locality itself; (3) our possibly imperfect knowledge of the struggle which is waged there now.

B. Poulton

From Nature 12 March 1903.

50 YEARS AGO

The Nutrition Society held a symposium on 'The Role of Vitamins in Metabolic Processes' in the Biochemistry Department of the University of Sheffield on December 20, 1952... . In the final paper, Dr. L. J. Harris (Dunn Nutritional Laboratory, Cambridge) examined the literature which, despite its bulk, still leaves us without evidence for a specific metabolic role of vitamin C. Among older hypotheses was one associating ascorbic acid with collagen formation, and also the more general theory that certain formative cells, such as osteoblasts, show reduced activity; in these cells the vitamin has been found to be concentrated in the Golgi apparatus... The great majority of animals can synthesize vitamin C, but, although glucose is known to be its precursor, it is still not known whether synthesis is a property of all cells of the body, or whether certain tissues are specialized for this purpose; similarly, the function of the vitamin in plants is still obscure.

From Nature 14 March 1953.