554 



THE NATURE BOOK 



far as ni}^ own experience goes, Adders 

 invariably strike downwards, after a 

 suitable disposition of the coils, a pro- 

 longed vibration of the tongue, and a 

 warning hiss. Cases of Adders getting 

 home above the level of the ankle-joint 

 must, I fancy, have tlieir origin in a 



PHOTOGRAPHS OF THE BONES OF ONE SIDE 

 OF AN ADDER'S SKULL (x 3). 



To show the mechanism by which the fangs are broufiht 

 into a convenient position for striking. It should be 

 noted that in order to secure a clearer view of the 

 transverse bone T, a portion of the fore part of the skull 

 has been cut away, and that its original position is 

 indicated by dotted lines. It should also be noted that 

 the two fangs visible both belong to the same side of 

 the head, one being a fully developed and functional 

 supernumerary. The star on the left hand marks the 

 posterior end of the squamosal S, which may be 

 regarded as a fixed pivot. With this bone, the quad- 

 rate O articulates, and with this again the mandible M' 

 articulates, and the pterygoid P, both of which carry 

 small recurved teeth. Fixed to the centre of the ptery- 

 goid is the transverse bone T (ecto-pterygoid) the 

 anterior end of which is connected by ligaments with 

 the maxillary M. This carries the fang F (two fangs in 

 this particular instance), and is hinged to the fore part 

 of the skull at the point indicated by the star on the 

 right, the second fixed pivot. 



The mechanism is a linkage between the two fixed 

 pivots indicated by the stars. 



1 shows the fang at rest. In Fig. 2 the quadrate Q 

 and the mandible M' have swung downwards, pushing 

 out the pterygoid P. The transverse bone T necessarily 

 comes forward with the pterygoid, and has rotated the 

 maxillary M on its hinge, so that the fang F is " erected." 



Fig. 



spasmodic bucking action in an Adder 

 which is trodden on, or otherwise very 

 rudely disturbed. The ordinary action 

 is like the flick of a whip. 



Deaths from Adder bite in this country 

 are extremely rare. Two fairly recent 

 instances are quoted in Professor Leigh- 

 ton's " British Serpents." In the first 

 (June 2nd, 1893, Glamorgan) a boy 

 eleven and a half years of age was seen 

 professionally within three-quarters of an 

 hour of the accident, and died within 

 thirty-six hours. In the second (June, 

 1 90 1. Cumberland), a child aged four 

 years and eight months was bitten in the 

 leg, and died three days subsequently. 

 In this case it was some hours before 

 medical assistance could be obtained. 

 So far I ha\'e been, personally, fortunate 

 enough to escape being bitten, but several 

 cases of severe Adder bite have come with- 

 in my experience. The primary symptoms 

 are faint ness (sometimes alarming faint - 

 ness) and pain in the wound ; the second- 

 ary, ulceration of the wound and a swollen 

 condition of the hmb (it is almost always 

 the hand which is bitten), which may 

 extend to the adjacent trunk — the symp- 

 toms, that is to say, of severe local blood- 

 poisoning. One victim who was bitten 

 near the wrist, and who felt the effects 

 for a fortnight, described his experience 

 as " much like vaccination." 



Scientifically, snake-poisons are termed 

 " venins," and have been assigned to the 

 group which embraces bacterial poisons, 

 such as those of tetanus and diphtheria, 

 scorpion poisons, and deadly vegetable 

 poisons, such as ricin and abrin. 



The complexity and variability of 

 snake-poisons is a serious hindrance to 

 the disco\-ery of any treatment by which 

 a human being may be rendered immune. 



So far as tliis country is concerned, 

 we may congratulate ourselves that the 

 vast majority of snake bites occasion no 

 more than a few days' discomfort. In 

 view, however, of the two pitiable instances 

 to which I have alread}^ referred, I feel 

 I need make no apology for indicating the 

 treatment which doctors advise. Since 

 snake-poison powerfully depresses the 

 heart, the first object is to prevent the 

 venom getting into the circulation. Much, 

 of course, depends on the position of the 

 wound. If the Adder's fang happens to 



