ON September 2, the physiologists of the British Association for the nonce forsook their frogs, cavies, rabbits and almost, but not quite, their rats. They left the cloistered calm of controlled experiments in camera and the discussion of intricate problems of nerve conduction or surface films, interesting, no doubt, to those who have at least mastered the terminology but deadly dull to those who have not, and descended to the world of men, and to a consideration of the criteria of the healthy life both of man as an individual and as an integer in a community. They could not, however, quite part with the rat. The important part this rodent has played and is still playing in the progress of civilization would need a whole article to describe, but we only heard of its value in assaying food for certain vitamins, and were warned of the dangers of accepting results obtained from experiments on rats as applicable without reserve to man. For example, the anti-vitamin D influence of cereals— so clearly demonstrable on rats and puppies, due to the absence from their alimentary tracts of an enzyme capable of freeing phosphate from phytin— leads to low-phosphorus rickets, a condition unknown in man. The breakfast cereal, whether provided dry or as Scots porridge, thus leaves the physiological court of appeal without a stain on its character, or, to be more cautious, with the Scots verdict "not proven".