500 poisons: their effects and detection. [§§ 653-656. 
Zealand. Mr W. H. Wright has recorded the case of a person who, in 
1865, was bitten by this spider on the shoulder. The part rapidly 
became swollen, and looked like a large nettle-rash wheal; in an hour 
the patient could hardly walk, the respiration and circulation were both 
affected, and there was great muscular prostration ; but he recovered in 
a few hours. In other cases, if the accounts given are to be relied upon, 
the bite of the spider has produced a chronic illness, accompanied by 
wasting of the body, followed by death after periods varying from six 
weeks to three months. 1 
§ 653. Ants. —The various species of ants possess at the tail special 
glands which secrete formic acid. Certain exotic species of ants are 
provided with a sting, but the common ant of this country has no special 
piercing apparatus. The insect bites, and then squirts the irritating 
secretion into the wound, causing local symptoms of swelling and 
inflammation. 
§ 654. Wasps, etc. —Wasps, bees, and hornets all possess a poison-bag 
and sting. Josef Lauyer ( Archiv f. exp. Pathol ., 1897) collected the 
stings and poison-bags of 25,000 bees. These were treated by a modified 
Stas-Otto process, and ultimately a substance obtained which gave pro¬ 
nounced alkaloidal reactions. Intravenous injection of 6 c.c. of 1-5 
per cent, solution of the natural poison killed a dog weighing 4*5 kilos. ; 
there were general convulsions, with trismus, and nystagmus rising to 
emprosthotonos, and the animal died from the cessation of respiration. 
The poison dissolves the blood corpuscles, and the post-mortem appear¬ 
ances show strong hyperaemia and haemorrhages. 
§ 655. Cantharides. —Commercial cantharides is either the dried 
entire or the dried and powdered blister-beetle, or Spanish fly ( Cantharis 
vesicatoria). The most common appearance is that of a greyish-brown 
powder, containing shining green particles, from which cantharidin 
is readily extracted by exhausting with chloroform, driving off the 
chloroform by distillation or evaporation, and subsequently treating 
the extract with bisulphide of carbon, which dissolves the fatty matters 
only. Finally, the cantharidin may be recrystallised from chloro¬ 
form, the yield being *380 to *570 per cent. Ferrer found in the wings 
and their cases -082 per cent. ; in the head and antennae, *088 ; in 
the legs, -091 ; in the thorax and abdomen, -240 per cent. Wolff 
found in Lytta aspero, -815 per cent. ; Ferrer in Mylabris cichorei , 
•1 per cent. ; in M. punctum. -193 ; and in M. pustulata, -33 per cent, 
of cantharidin. 
§ 656. Cantharidin (C 10 H 12 0 4 ) has two crystalline forms — (1) 
right-angled four-sided columns with four surfaces, each surface being 
beset with ne'edles ; and (2) flat tables. It was at one time considered 
1 Transac. of the New Zealand Inst., vol. ii., 1869 ; Brit, and For. Med. Chir. 
Review, July 1871, p. 230. 
