I regularly weighed the dry residue from eleven bites made on a watch-glass by two _Naja haje_, received at my laboratory from Egypt at the same time, and placed in the same case. Both snakes were approximately of equal length, 1,070 millimetres. Throughout the entire course of the experiment, which lasted _one hundred and two days_, neither of them took any food, but they drank water and frequently bathed. The results that I obtained are shown in the table on next page. It will be seen that in one hundred and two days, an adult _Naja haje_ is capable of producing on an average 0·632 gramme of liquid venom, equal to a mean weight of 0·188 gramme of dry extract; and we may conclude that 1 gramme of _liquid_ gives 0·336 gramme of _dry_ venom. In Australia it has been found by MacGarvie Smith, of Sydney, that _Pseudechis porphyriacus_ yields at each bite a quantity of venom varying from 0·100 gramme to 0·160 gramme (equal to 0·024 gramme to 0·046 gramme of dry venom), and that a _Hoplocephalus curtus_ (Tiger Snake) yields 0·065 gramme to 0·150 gramme of liquid venom, with 0·017 gramme to 0·055 gramme of dry residue. In all the experiments of this physiologist, the proportion of dry residue varied from 9 to 38 per cent. of the liquid venom excreted by the reptile. A _Lachesis lanceolatus_ (Fer-de-lance) from Martinique, of medium size, when both of its glands were squeezed, furnished me with 0·320 gramme of liquid venom, and 0·127 gramme of dry extract. +---------+----------+-------------------+-------------------+ | | | _NAJA HAJE_ I. | _NAJA HAJE_ II. | |Number of| Date | WEIGHT OF VENOM | WEIGHT OF VENOM | | bite | +---------+---------+---------+---------+ | | | Fresh | Dry | Fresh | Dry | +---------+----------+---------+---------+---------+---------+ | | | Gramme | Gramme | Gramme | Gramme | | 1 | April 20 | 0·119 | 0·031 | -- | -- | | 2 | “ 23 | -- | -- | 0·151 | 0·043 | | 3 | May 14 | 0·124 | 0·035 | -- | -- | | 4 | “ 21 | -- | -- | 0·132 | 0·037 | | 5 | “ 28 | -- | -- | 0·091 | 0·019 | | 6 | June 2 | 0·127 | 0·039 | -- | -- | | 7 | “ 19 | -- | -- | 0·121 | 0·043 | | 8 | July 1 | -- | -- | 0·078 | 0·026 | | 9 | “ 2 | 0·122 | 0·048 | -- | -- | | 10 | “ 25 | -- | -- | 0·111 | 0·034 | | 11 | “ 26 | 0·079 | 0·021 | -- | -- | +---------+----------+---------+---------+---------+---------+ | | Totals | 0·581 | 0·174 | 0·684 | 0·202 | +---------+----------+---------+---------+---------+---------+