extremely acrid fluid: in colour, they are of a beautiful purple, with an admixture of crimson; and they are covered by a glutinous substance, having a peculiar odour. The inflated membrane is probably intended to keep the animal buoyant on the water, by which it is readily enabled to extend its long tentaculæ in search of prey, or it may be designed as a locomotive agent, aiding the animal in its progress over the “vast bosom of the ocean,”—thus serving the purpose of a sail. It is said that the appearance of the _Physalia_ near to the sea-coast is the indication of an approaching tempest.[6] Having captured a very fine specimen of this animal on a former voyage in latitude 9° 0′ south, and longitude 12° 59′ west, and being aware of the pungent property residing in the tentaculæ, I was desirous of trying its effects on myself, for the purpose of ascertaining from personal experience the constitutional irritative effects resulting from it. On taking hold of the animal it raised its tentaculæ, and stung me on the second and ring fingers. The sensation was similar at first to that produced by the nettle; but before a few minutes had elapsed, a violent aching pain succeeded, affecting more severely the joints of the fingers, the stinging sensation at the same time continuing at the part first touched by the acrid fluid. On cold water being applied, with the intention of removing or lessening the pain, it was found rather to increase than diminish the effects. The irritation resulting from the poisonous fluid emitted by the animal extended upwards, increasing in extent and severity, (apparently acting along the course of the nerves,) and in the space of a quarter of an hour, the effect in the fore-arm (more particularly felt at the inner part) was very violent, and at the elbow-joint still more so. It may be worthy of remark, that when the joints became affected the pain always increased. It became at last almost unbearable, and was much heightened on the affected arm being moved; the pulse of that arm was also much accelerated, and an unnatural heat was felt over its whole surface. The pain extended to the shoulder-joint; and on the pectoral muscle becoming attacked by the same painful sensation, an oppression of breathing was occasioned, which we find similarly produced by rheumatism, when it attacks that muscle; and it proved very distressing during the time it remained. The continuance of the pain was very severe for nearly half an hour, after which it gradually abated, but the after effects were felt during the remainder of the day in a slight degree of numbness and increased temperature of the arm.