10 T. P. ANDERSON STUART. 



to believe that the Sydney varieties are poisonous, at all events in 

 certain seasons, though I got no results from hypodermic injection 

 in dogs except profuse vomiting. I could not induce the spiders to 

 "bite," and so I had to make extracts of the glands or rather of 

 the entire body. Just at this stage, my friend Professor Kobert, 

 of Dorpat, wrote to me, telling me that he had been investigating 

 Lathrodectus tredecempunctatus, which he said was the most 

 poisonous spider in the world, and that he had obtained therefrom 

 the most powerful poison up till that time known, for 0-00003 

 gramme per kilogramme weight of animal injected into the blood 

 was fatal. A better idea of what this really means will be con- 

 veyed if I tell you that at this rate one twenty-eighth part of a 

 grain injected into the blood of a man twelve stone weight would 

 be fatal. Brieger has also found in the " Caracurt," or " Black 

 Wolf," a poison making up twenty-five per cent, of the body 

 weight, and of about the same power as the poison of the Lathro- 

 dectus. I collected and sent to Dr. Kobert some Lathrodecti from 

 St. Leonards, near Sydney, but these yielded negative results. I 

 am therefore inclined to think that this insect is not always in a 

 poisonous state, but what are the conditions I do not know, for 

 in a poisonous state a single spider should be able to kill many 

 dogs. The records of cases of the bite in man are neither numer- 

 ous nor complete in the medical literature of Australasia, while 

 the stories of the spiders are well known to everyone. Such is 

 the "Katipo" (Lathrodectus lugubris) of New Zealand, which is, as 

 it appears to me justly, credited with fatal results to human adults, 

 though, on the other hand, it, too, has been found in a not very 

 poisonous condition. An interesting account of the poisonous 

 and fatal results of the bite of the Katipo may be read in Dr. F. 

 W. Wright's paper in the Transactions of the New Zealand 

 Institute for 1869. From these particulars, then, it will be seen 

 that there is quite a field open as regards Australasian spiders alone. 



POISON OF THE AUSTRALIAN BUSH-TICK. 



The question of the poisonousness of ticks is an interesting one, 

 for on the one hand dogs, cats, small marsupials, and snakes are 



