FATE OF ARSENIC AFTER INGESTION UV LIVESTOCK. 473 



very small. Elimination begins at once, and several per cent, 

 '/if the injected amount may appear within half an hour. As 

 much as 70 per cent, ma}' appear within 24 hours, the amount 

 then rajiidly tailin^j- off until at the end of five or six days over 

 ijo per cent, may have been recovered. I'^urther elimination 

 is gradual and trifling in daily amoimt. 



After injection into the blood-stream the concentration of 

 arsenic in the blood falls with extraordinary rapidity by tem- 

 porary distribution over the tissues. The rapidity and nature 

 of this distribution is discussed. 



The data for horses and cattle are more limited, largely 

 owing to the greater experimental difficidties presented by the 

 collection of faeces and urine of large animals. With the horse, 

 however, the absorjition of soluble arsenic seems to be less com- 

 plete, and a larger ])ro]x:)rtion of any gi\en (l(ise appears in the 

 faeces. 



The amount of arsenic eliminated by cattle and horses after 

 dipping in arsenical tanks is very small, and the currentlv 

 accepted data are shown to be erroneous. Currently accei)ted 

 data for arsenic retained in the skin of dii>ped animals are also 

 shown to be much too high. The bearing of these ])()ints on 

 the modus operandi of tick destruction is discussed. 



The quantity of arsenic to be ex])ected in organs such as 

 the liver in cases of arsenical intoxication, is considered, and 

 the difficulties of diagnosing arsenical poisoning in stock in 

 S(".uth Africa are discussed. 



( Read. J Illy 5, IQ17.) 



NEBULiE AND NOYJE — Dr. \'. M. Slipher contributed 

 some time ago to the Proceedings of the American Philosophical 

 Society a paper on Nebul;e, in the course of which he remarked 

 that it has for a long time been suggested that the spiral nebulae 

 are stellar systems seen at great distances. This is the so-called 

 " island universe " theory, which regards our stellar s\stem and 

 the Milky Way as a great spiral nel)u]a wliich we see from within. 

 This theory, Dr. Slipher considers, gains in favour l)y reason 

 of the spectrographic observations conducted at the Lowell 

 Observatory since 1912, but he thinks that, if our solar system 

 evolved from a nebula, as was long believed, it was probably not 

 one of this class of spirals. In the course of some notes on 

 \ariable stars contributed to the Report of the Council of the 

 Royal Astronomical Society,* the Rev. T. E. R. Phillips declares 

 that it is unthinkable that the apparent relationship between Novae 

 and spiral nebulae in so many instances can be fortuitous. The 

 Novae must almost certainly be In the nebulae, and this circum- 

 stance, taken in conjunction with the well-known clustering of 

 Novae in our galaxy towards the galactic plane, seems highlv 

 significant, and gives striking supjwrt to the theor\- that the 

 spirals are '' island universes." 



* .'[fniifhiy ynficcs (lQt8). 78 U^. .^"Q. 



