ACARINA 



215 



commoner heading of Mygale, and cause prolonged inflammation 

 and extensive cicatrization. Theraphosa javanensis is reported to 

 kill men. 



Bite of Chcetopelina olivacea.- — ^The local symptoms are great 

 pain, redness, swelling, but whether a g neral effect (curari-like 

 poisoning of the voluntary muscles and death from stoppage of 

 respiration) takes place is very doubtful. 



Bite of Lycosa tarantula. — The bite of this spider produces wheals 

 surrounded by a red areola, but no general symptoms result, and 

 tarantismus only exists in popular imagination. The tarantula 

 dance was probably introduced as a cure, with the purpose of 

 keeping the patient on the move, so that he should perspire, and 

 thus get rid of the poison. The tradition of the Middle Ages was 

 that the bite caused the dance frenzy, Chorea saltatoria, or taran- 

 tismus, which was supposed to lead to such violent exertion that 

 death resulted unless the victim was soothed by music. 



1 he Bile of Epeira diadema. — The bite of the common garden spider has 

 been recently proved by Robert and Sachs to be poisonous. 



The Bite of a Bengal Spider. — Fink has recently described a herpetic eruption 

 on the face of Bengalee children due to a spider-bite; for this he recommends 

 fumigating the face with the smoke evolved when lumps of mustard-oil cake,^ 

 burned in a charcoal fire, are dropped into a basin of cold water. 



Diagnosis.— Bee-stings, scorpion-bites, and ordinary skin bacterial 

 infections must, of course, be distinguished from spider-bites, with 

 which, without doubt, they have been often confounded. The 

 local symptoms and the history ought to be some guide. 



Prognosis. — ^This is generally good. 



Treatment.- — Prevent absorption by the proximal ligature, open 

 the wound by an incision, and apply alkaline solutions — e.g., weak 

 solutions of ammonia or carbonate of potash, or equal parts of 

 spirit of ammonia and water as a wet dressing. It appears to us 

 that a strong permanganate of potash solution ought to be given 

 a trial. 



3. Acarina. 



The Ixodoidea, or ticks, are well known to cause severe symptoms 

 by their bites, apart from the introduction of any parasite such as a 

 Piroplasma or Spirochceta. 



The anatomy of these arthropods is given in detail in 

 Chapter XXVIII., p. 689, to which reference should be made, but 

 a few remarks are necessary concerning the act of biting, which 

 has been studied by Nuttall. 



The tick pierces the skin by means of the teeth on the digits of 

 its chelicerse. The digit is capable of being extended by an internal 

 muscle, and turned outward by an external muscle. These move- 

 ments, occurring alternately, cause the teeth to cut the skin, and 

 as the chelicerae work deeper and deeper, the hypostome is dragged 

 into the wound, and by its recurved teeth keeps the tick in position. 

 The palps but rarely enter the wound. During this act of biting 

 it is believed that the salivary glands pour a considerable amount 



