23 



loopfnla o( apores. In each plate was placed a portion of camphor abont the 

 size of a large pea ; and the plates were incubated at SZ^O. In 24 hours 

 there was gocd growth ; but close to the lump of camphor, growth was 

 slightly inhibited. 



Thus, camphor in the quantity in which it might be kept in a hive has 

 no antiseptic effect, the amount used in the fxperiments being far larger 

 than would be used in a hive. This substance, therefore, if it has the effect 

 mentioned by those who have used it, must act as a stimulant, strengthening 

 the bees to overcome the disease. 



f4) Thyme. Klempin (62) has used branches of dry thyme with success, 

 burning them in the smoker for disinfecting his hives ; but their effect, like that 

 camphor, is not radical, and beekeepers are •not all in accord as to their 

 efficacy. 



(5) In connection with thyme thymol may be mentioned. Zehetmayr 

 (63) has recommended the use of thymol, and has made a little machine by 

 which he steams the bees with this substance. If a little of it is placed in a 

 hive it ^ill prevent infection, because bees from' uninfected hives will not 

 come near it, — they object to the smell, until they become accustomed to it. 

 Blow (63) thinks it very valuable, and Jones (65) remarks that, even in great 

 dilution, it prevents the growth of the germ ; but Cowan criticises its use, 

 because it is disagreeable to bees, and if used in sufficient quantity, acts as a 

 poison, and therefore cannot be good in food. 



Experiments on the antiseptic value df Thymol. Crystals of thymol were 

 placed in test tubes of sloped agar in our laboratory and inoculated with one 

 loopfnl of spores of B. alvei. These were capped with tin foil paper and 

 incubated at 22" and 37°0. 



Result. Control tubes — abundant growth. 



Thymol tube at 22°C.— slight growth. 



" " 37°C.— very slight growth. 



Agar plates, poured and streaked with two loopfuls of spores of B. alvei, 

 were used in another experiment ; and a piece of thj^mol the size of a large 

 pea was placed in each plate. The plates wern incubated at 37°, along with 

 control plates, with the following results : 



24 hours, control platen-abundant growth. 



" thymol plates^ — good growth, but close to the lump, no growth. 

 Hence we conclude that this substance has a very slight antiseptic effect. 



(6) Carbolic Acid and Tar. These substances were first used by 

 Schreuter (66) and they are applied as follows : — " A piece of felt wool is 

 placed in a small box, and soaked with a mixture of carbolic acid and ITor- 

 wegan tar, in equal proportions The cover of the hive is slightly raised, in 

 order to permit of the evaporation of the carbolic acid. The box is left upon 

 the platform of the hive beneath the brood, and remains there permanently. 

 The dose can be renewed as often as required. The addition of tar to the 

 acid is for the purpose of making evaporation take place more slowly." This 

 remedy has not been used to a very great extent. Borel (67) reports success 

 with it ; but others have not had the same results, and it is probable that it 

 should be used only as a preventive. 



Experiments on the antiseptic value of Carbolic Acid and Tar. ^ Four 

 drops of the mixture placed on blotting paper and inserted in a Petri dish 

 containing agar streaked with spores, inhibited growth, from which we see 

 that the mixture is antiseptic. 



(7) Greolin or Phenyle. Creolin has been recommended by Cowan (68) 

 and has been used with success by other apiculturists, 



