When dried rapidly in vacuo or in a desiccator over calcium chloride, it concretes in cracked translucent lamellæ like albumin or gum arabic, and thus assumes a crystalloid aspect. In this condition it may be kept indefinitely, if protected from light, air, and moisture. It dissolves again in water just as readily as albumin or dried serums.
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.
| Number of bite | Date | NAJA HAJE I. Weight of Venom | NAJA HAJE II. Weight of Venom | ||
|---|---|---|---|---|---|
| Fresh | Dry | Fresh | Dry | ||
| Gramme | Gramme | Gramme | Gramme | ||
| 1 | April 20 | 0·119 | 0·031 | — | — |
| 2 | April 23 | — | — | 0·151 | 0·043 |
| 3 | May 14 | 0·124 | 0·035 | — | — |
| 4 | May 21 | — | — | 0·132 | 0·037 |
| 5 | May 28 | — | — | 0·091 | 0·019 |
| 6 | June 2 | 0·127 | 0·039 | — | — |
| 7 | June 19 | — | — | 0·121 | 0·043 |
| 8 | July 1 | — | — | 0·078 | 0·026 |
| 9 | July 2 | 0·122 | 0·048 | — | — |
| 10 | July 25 | — | — | 0·111 | 0·034 |
| 11 | July 26 | 0·079 | 0·021 | — | — |
| Totals ... | 0·581 | 0·174 | 0·684 | 0·202 | |
Two large Cerastes vipers, from Egypt, yielded me, one 0·123 gramme, the other 0·085 gramme of liquid venom, which, after desiccation, left respectively 0·027 gramme and 0·019 gramme of dry residue.
Under the same conditions, a magnificent Crotalus confluentus (Mottled Rattle-Snake), for which I was indebted to the kindness of Mr. Retlie, of New York, yielded, two months after reaching my laboratory, 0·370 gramme of liquid venom and 0·105 gramme of dry extract in a single bite.
The total quantity of liquid venom that I found contained in the two glands of the same reptile, when extirpated after death, and after the snake had been in the laboratory for five months, amounted to 1·136 gramme, which gave 0·480 gramme of dry extract.