2IO VENOMOUS ANIMALS : PROTOZOA TO ARTHROPODA 



method by which it kills its prey, which usually consists of small 

 animals; and, further, that, in order to be toxic, the venom must 

 be injected subcutaneously or intravenously, for by the mouth it 

 is harmless. 



When experiments are performed on animals, the following 

 symptoms appear: — - 



1. Local irritation and pain. 



2. Muscular twitchings, chiefly of the head and neck. 



3. jumping movements. 



4. Lachrymation. 



5. Increased orbital, nasal, and salivary secretions. 



6. Muscular spasms, especially of the hind-limbs, but also in all 

 muscles. 



7. Erection of the hairs. 



8. Passage of liquid faeces (often absent). 



9. Erection of penis and emission of semen. 



The venom of Scorpio maurus causes death in small birds within 

 two minutes to half an hour from failure of the respiration. If 

 the venom of a scorpion is placed on the conjunctiva of a rabbit, 

 violent ophthalmia results. 



In man, the symptoms depend upon the size and nature of the 

 scorpion. Thus, the sting of the small (3J centimetres) Euscorpius 

 europcBus causes only pain, redness, and local swelling, whereas 

 the larger tropical scorpions cause very intense pain of a burning 

 character radiating from the skin, associated often with violent con- 

 vulsions, mental disturbance, and hallucinations, profuse perspira- 

 tion, and secretion of saliva, and perhaps vomiting. The pulse is 

 weak and quick, and the respirations hurried and shallow. These 

 symptoms gradually diminish in three to eight hours, and by about 

 nineteen to twenty-four hours the person is usually normal. This, 

 however, is not always so, for death may ensue due to collapse 

 or stoppage of the respiration, effects which are more likely to 

 happen in small children than in adults. Thus, Wilson states 

 that the mortality in children under five is 60 per cent, for Buthus 

 quinquestriatus, but the mortality diminishes as the age increases. 

 Of course this is simply due to the greater dilution of the poison in 

 the body of the adult. 



In addition to the above symptoms, some authors have described 

 trismus, but it is probably due to infection with the bacillus of 

 tetanus. The erection of the penis noted in experiments on animals 

 has been seen in man by Delange and Guy on in Algeria. A paralysis 

 of the lingual and hypoglossal nerves has been noted by Posada- 

 Arango. Lymphangitis and adenitis are described as part of the 

 local effect of the sting. 



The above symptoms would indicate the action of a neurotoxin 

 acting upon the nervous system, and causing first of all increased 

 reflex action and convulsions, and later paralysis of the medullary 

 nuclei; for if Valentin's observations are correct, there are no 

 paralyses of the motor nerve-endings. 



