187 



for six generations," it proved to be, a glucoside poison (probably 

 squills) and contained no bacteria of any kind. A number of experi- 

 ments were made mih it, and it proved to be an effective rat poison. 

 In some instances the animals died within two hours after eating it, 

 and in two experiments all the animals fed died within twelve hours. 

 In other experiments, however, a considerable percentage of the 

 affected rats recovered, and subsequent attempts to kill them with 

 ratin No. 2 failed. Some were immune to its effects and others too 

 wise to eat it a second time. More than a hundred rats were used in 

 the experiments; but the main object — to test the communicability 

 of the disease caused by ratin bacteria in healthy rats — failed, of 

 course, since, as above stated, the preparation experimented with 

 contained no bacteria, but was merely a vegetable poison. Before 

 its character was fully determined, 15 rats killed in the experiments 

 were eaten by 5 healthy rats; the latter were unaffected. 



It should be noted that the labels on the tins containing trans- 

 Atlantic ratin were misleading. The user was warned to open the 

 packages in dim light and to allow no moisture to come in contact 

 with the contents, as the bacteria were very sensitive to light and 

 moisture. The contents of the can were to be used at once. As a 

 matter of fact the contents of one can were exposed to severe, drying 

 in heat and sunlight for four days and then soaked in water for two 

 days. Afterwards the preparation was fed to different rats for a 

 further period of four days, and its virulence was retained to the last. 



The trans-Atlantic ratin is in a solid medium, apparently bread 

 and molasses. Its keeping qualities are excellent, and it is an effect- 

 ive poison for rats, but far too expensive for extensive use. A can 

 costing $1.50 is enough for only 15 baits. 



Its harmfulness to domestic animals was not fully tested. Dogs 

 and cats refused to eat it and vomited it when it was forced upon them. 

 Several animals, including a dog, were killed by injections of the 

 poison in concentrated form. 



A shipment of ratin No. 1 (the solid bacterial ratin, said to retain its 

 virulence for two months) was received June 4, 1909. This prepa- 

 ration was dated May 8 and should have been still virulent. The con- 

 tents of a can mixed with milk was fed to 8 adult rats on June 7. All 

 of the baits were eaten, but no result followed. Cultures of the 

 bacteria showed strong growths of new colonies. 



On July 6 the contents of another can were fed to 1 adult and 16 

 young rats. One of the young was found dead on the morning of 

 July 14. Cultures were made from the dead rat, but the bacUlus 

 was not recovered. Up to July 28 none of the other rats have been 

 affected. 



