December, 1905.J 



KNOWLEDGE & SCIENTIFIC NEWS. 



299 



tracts from the leg's or the abdomen proved just as 

 venomous as those made from the chephalo-thorax. 

 New-born spiders were more venomous than adults, 

 and the cocoons and eggs more venomous still. 



I^xtracts from the dreaded tarantula were found to 

 be quite innocuous, and this was also the case with 

 all the other families of spiders examined, with the ex- 

 ception of the common garden spider {Aranea diademata 

 [Epeira diadcma]), which yielded extracts producing 

 very similar toxic effects. Both caused paralysis of the 

 respiratory system and heart, accelerated the coagula- 

 tion of the blood, and had a, strong solvent (haemolytic, 

 action upon the red blood corpuscles. 



The fact that all parts of these spiders were poison- 

 ous is analogous tO' what has been observed in the case 

 of snake venom, which is not confined tO' the poison 

 glands alone, for it has been proved that the blood of 

 poisonous snakes is also venoi7ious. 



Dr. Robert also confirmed Toti's statement that the 

 venom is harmless when swallowed, and this is another 

 point in which it resembles snake venom. 



He further succeeded in rendering animals immune 

 against the venom by inoculating them with gradualh 

 increasing doses, and their immunised serum conferred 

 protection on other animals. 



Both the lathrodectes poison and the poison of the 

 garden spider were destroyed by heating them at a 

 comparatively low temperature, and bv the addition of 

 alcohol, but the former was somewhat more stable than 

 the latter. 



Dr. Kobert concluded that both were of the nature 

 ol " toxalbumins," i.e., substances resembling white of 

 egg in chemical composition, but possessing toxic 

 powers. 



Many poisons, however, including snake venom, 

 which were formerly regarded as toxalbumins, have 

 been found when properly purified to be free from 

 albuminous substances, and doubtless this will be 

 found to be also the case with spider venom. 

 (To be continued .) 



Consvimption of Tobacco. 



In the Department of Commerce of the L'nited States 

 some statistics have been drawn up regarding the con- 

 sumption of tobacco during recent vears per head of 

 population in different countries. The following are 

 the results : — 



Royal Institution. — A Christmas Course of Lectures, 

 adapted to a juvenile auditory, will be delivered at the Royal 

 Institution by Professor Herbert Hall Turner, D.Sc, F.R.S., 

 on •'Astronomy." The dates of the Lectures are December 

 2S, 30, 1905, January 2, 4, 6, and 9, 1906, at three o'clock. 



CORRESPONDENCE. 



To THK KniToKs III- " Knowledge." 

 Gentlemen, — In the three accounts of the recent eclipse 

 published in " Knowledge" last month, there are consider- 

 able discrepancies as regards the position of the two groups 

 of prominences. It is with extreme reluctance that I venture 

 to differ from so eminent an observer as M. Moye. But my 

 observations, aided by a telescope, were made very carefully, 

 and I saw no prominence, much less a group, in the southern 

 hemisphere. I send a diagram which shows outside the circle 

 twelve prominences marked at the telescope. One is double- 

 stemmed, and one is floating. Within the circle I have 

 marked those shown in Fr. Cortie's six photographs, done at 





foivit 



the same time and place. The agreement is substantially 

 exact. In the N.-E. quadrant, No. 5 was of very great height. 

 Though it appeared the first, it is visible in the last of the 

 photographs, taken at the very end of totality. On both 

 sides of No. 5 there is a long blur of light in the first 

 photograph, like the elevation of that length of the sierra. 

 This was not noticeable in the telescope, probably owing to 

 the very pale tint of the chromosphere and prominences. 



My eye-piece was divided by spider threads into quadrants, 

 and the north point approximately fixed by running sunspots 

 along the horizontal wire. 



Yours faithfully, 



ArorsTiN Moreord. 

 The Friary, Saltash, Cornwall, 

 November 8, 1905. 

 [In our article in the October number occurs the sentence, " Photo- 

 graphs alone can give us the true position and dimensions of the 

 prominences," and these eye sketches, valuable as they are in 

 many respects, must give way before the incontrovertible evidence 

 of the photographic plate. — Ed] 



Answers to Correspondents. 



tiamina. The white-hot part of a coal fire is at a temperature 

 of over 2300 Fahrenheit, though in an ordinary domestic fire 

 it seldom attains a real white heat. .-\ dull red- heat is about 

 1200'^ F. 



Rev. M. McLean. This was the aurora borealis, described on 

 p. 293. It is very rarely seen so distinctly in England. 



