ECONOMIC ZOOLOGY ENTOMOLOGY. 753 



structed by the mole serves as passageways for several species of mice, winch 

 are aloue responsible for most of the damage to seeds, roots, and tubers encoun- 

 tered in the soil. The best method of combating the mole is by means of a trap 

 in the hands of a person who linows how to set it. Crystals of strychnin in 

 raisins or bits of fresh meat make fairly effective poison baits. 



" Mice which take seed corn in the ground may be destroyed by introducing 

 poisoned grain baits into mole runways throughout the field. The theft of seed 

 corn may sometimes be prevented by treating it with coal tar, tobacco decoction, 

 or stock dip before planting." 



Rat virus in Jamaica, S. F. Ashby (Bui. Dept. Agr. Jamaica, n. scr., 1 

 (1909), No. 2, pp. 97-102). — An account is given of rat viruses and the work 

 with them at the government laboratory. 



During the 3 months, June, July, and August, 1908, 2,078 rats inoculated 

 with a Danysz virus, which has been adapted to the field rats of Mexico, were 

 distributed in town and country. After an interval of a month, 72 replies were 

 received accounting for 1,.500 of the rats distributetl. Twenty-two of these 

 reported a disappearance of all rats, which showed success in conveying the 

 infection to healthy ones, for about 20 per cent of the rats distributed and 30 

 per cent of the localities selected. 



The best results with Danysz virus received from London were obtained when 

 the virus was grown in milk at a constant temperature for 24 hours, irrespective 

 of whether the temperatures were from 68 to 98° F., even with the adapted 

 virus, however, the method of treatment recommended by the Danysz agency 

 proved very uncertain. "The Mexican vii'us, Danysz virus, Liverpool virus, and 

 Azoa contain the same organism, and the success obtained either with the 

 original preparations of those or any of tlie other kinds tried is either very 

 uncertain or totally wanting." 



Notes from the bacteriological laboratory, S. F. Ashby (Bui. Dcpt. Agr. 

 Jamaica, n. scr., 1 (1910), No. 3, pp. 175, 176, pi. 1). — Since the account above 

 noted was prepared, the method of cultivating the Danysz virus in milk has 

 been further tested and developed. 



"A procedure which has repeatedly secured a mortality of SO per cent or 

 more within 10 days in experiments on caged rats is the following : The virus 

 is grown for one or two days on an agar slope at blood heat ; the growth is 

 transferred to about a quart of sterile milk which is incubated for one day at 

 blood heat and then soaked into small cubes of white bread which have been 

 well dried. The sponge obtained in that way is packed at once closely into tins 

 and sent away for distribution without delay. The bait should be set within 

 24 hours of preparation and kept cool in the meantime. It is scattered in likely 

 places in small portions loosely wrai)ped in paper of the kind used for printing 

 newspapers. . . . Rats appear to take Ihis bread milk bait very readily and 

 should contract disease and die within 10 days." 



Three of several mongoose on which this virus was tested contracted the 

 disease and died within a few days after being fed living rats which showed 

 symptoms of disease caused by the virus that had been fed to them. The 

 specific organism was obtained from the spleens of the dead mongoose and 

 cultures of it inoculated into rats killed them in the way characteristic of the 

 virus. 



Measles and mice. — Does the microbe of measles come from the mouse? 

 A. F. A. King (Washington Med. Ann., 9 (1910), No. I, pp. .',9-(;i ; ahs. in Jour. 

 Anier. Mrd. Assoc, 5'f (1910), No. 18, p. I.'t79). — Numerous instances are cited 

 which point to an etiologic relationship between mice and measles. 

 65483°— No. 8—10 5 



