686 EXPERIMENT STATION RECOED. [Vol.38 



every half hour for two liours, and measuring the amount of sediment remain- 

 ing after centrifugation. From the experimental data obtained the following 

 conclusions were drawn : 



Dakin's hypochlorite solution has the power of dissolving necrotic tissue, 

 pus, and plasma clot in the concentration and reaction used clinically, but the 

 other antiseptics tested do not show this action. The solvent action of Dakin's 

 solution is due primarily to its hypochlorite content, but its slight alkalinity 

 increases the effectiveness of the liypochlorite. The hypochlorite concentration 

 at which the solvent action cea.ses is lower the more alkaline the solution, and 

 in the degree of alkalinity used clinically the minimum concentration for solvent 

 action is about 0.2 per cent. None of the antiseptics studied lias a solvent 

 action on blood clot. 



These results do not support the clinical observations of Sweet (E. S. R., 37, 

 p. 876) and others that the more recent and more stable chloramins are more 

 effective in dissolving dead tissues than the older chlorin compounds. The 

 greeter solvent action of Dakin's solution the author assumes to be due to its 

 greater instability. 



Methods of controlling blackleg developed by tlie Kansas State Agricul- 

 tural College, L. W. Goss (Kansas Sta. Rpt. 1916, pp. U-^9).—As a result of 

 investigations continuing those previously noted (E. S. R., 36, pp. 180, 578), 

 " a serum has been produced from the horse which will stop immediately the 

 losses in a herd in which calves are dying from blackleg. Also, a germ-free 

 fluid vaccine or aggressin has been produced from calves, which when used 

 upon healthy calves will produce a more durable immunity against blackleg." 



The serum is prepared by five successive injections, from 7 to 10 days apart, 

 of pure cultures of Bacillus chauvwi into the jugular vein of a horse. Nine 

 days after the la.st injection a sample of blood is drawn and 0.55 cc. of the 

 clear serum injected subcutaneously into each of three guinea pigs which are 

 15 hours later injected subcutaneou.sly with 125 mg. of dried muscle from a 

 blackleg lesion of a calf. If the test is satisfactory the horse is bled upon the 

 third day and the clear serum bottled after the addition of 0.5 per cent of 

 phenol. The serum produces only a passive immunity, but active immunity 

 may be acquired by following the serum inoculation In three days with from 4 

 to 8 mg. of a virus made from the darkest meat of a blackleg lesion of a calf. 

 This is ground, passed through an SO-mesh sieve, and made into pellets which 

 are then attenuated at 60° C. for an hour to kill nonspore-forming organisms. 



The germ-free fluid vaccine or aggressin is made by the inoculation of calves 

 with muscle virus in doses of 1 gm. or by the use of from 20 to 30 cc. of pure 

 cultures of B. cJiauvcei. After the death of the calf the affected tissue is re- 

 moved, ground, frozen, thawed, and filtered through infusorial earth filters. The 

 filtrate is sterilized with 0.5 per cent of phenol or 1 per cent of chloroform and 

 tested for potency and sterility by subcutaneous inoculation of guinea pigs with 

 10 cc. of the vaccine. 



The blackleg serum is curative in the early stages of the disease and will 

 check outbreaks within 12 to 24 hours. The germ-free vaccine will not cure 

 blackleg but will produce immunity within four or five days after inoculation. 

 This immunity is of longer duration than that produced by the powder or pill 

 form of vaccine. It is advised that " serum should be used upon animals with 

 symptoms of blackleg. Serum and pellets should be used upon herds in whicli 

 losses are occurring at the time of vaccination. Germ-free fluid vaccine should 

 be used as an annual vaccination upon calves at weaning time or earlier, should 

 conditions indicate necessity." 



The eradication of tuberculosis from cattle and swine, J. A. Kieknan 

 (Amer. Jour. Vet. Med., 13 {1918), No. 1, pp. 1-7). — A paper presented at the 



