1921.] 



Research (T{at) Laboratory, 



715 



The work of the Laboratory inchides the chemical examination 

 ■of various proprietary raticides on the market as well as many 

 rat poisons the formulae of which are supposed to be secret but 

 which usually prove to contain nothino" ptartlin<>-. In addition, 

 raw materials purchased for the factory, or submitted from out- 

 side sources, are examined and toxicological analyses made in 

 cases where rat poison is suspected. A large amount of work 

 is done at the request of firms who manufacture or are desirous 

 of manufacturing raticides and are anxious to ensure that their 

 preparations are toxic. A good deal of investigation iias been 

 ■carried out on the various poisons in use as raticides, especially 

 Barium Carbonate, Eed Squills (Scilla mariiima), Sodium 

 Pluoride, etc. 



As an example of the problems to be solved, an account of 

 the Eed Squill referred to above may be interesting. The Eed 

 Squill is a bulb not unlike a large reddish onion and varies from 

 l- lb. to 2 lb. in weight. It grows in various countries on the 

 ^Mediterranean littoral. Very little is known of the chemistry 

 of this plant, and the little that has been published is scattered 

 in various German books, making progress slow. The plant 

 is similar to the Squill of medicine,, and its poisonous properties, 

 so far as rodents are concerned, have b.een known for a very 

 long time, though the white medicinal bulbs do not appear to 

 l3e poisonous to rats. In the raw state the bulb is poisonous, but 

 halts containing chopped -up bulb do not retain their toxicity very 

 long. If, however, the bait be cooked its keeping quality is 

 greatly increased. The bulbs when dried and powdered are also 

 "toxic, though the powders thus made vary a good deal, and the 

 ■exact conditions necessary for ensuring maximum strength are 

 not understood. The minimum lethal dose of powdered bulb 

 tor a medium-sized rat is from 1 to 2 grains. A liquid poison 

 can also be obtained bv steeping the bulbs in water and 

 pouring off the liquor. If kept in tightly-stoppered vessels this 

 •extract keeps toxic for a considerable time. The actual poisonous 

 substance in these bulbs is not known, though two or three 

 substances are said to have been isolated, but the descriptions 

 are very conflicting. Whatever it is, it must be fairly powerful. 

 Further, it is not known whether the toxicity of the bulb varies 

 at different stages of its growth, though this is very likely, and 

 it is important to know when it is most toxic. Neither is much 

 l;nown as to the exact quantity required to kill domestic animals, 

 though it is certainly relatively large. A South African variety 

 Squill iVrginea Burhei) is being investigated. It appears to 



