166 ItUEDIGER. 



The results obtained showed that the virus passed through Chamberland filters 

 marked F hut not through those marked B. 



Memmo, Martoglio and Adam' came to the conclusion that the virus of cattle 

 plague passes through the Berkefeld filter, but is arrested by the Chamberland. 

 These authors experimented with virulent blood diluted with physiologic salt 

 solution and filtered under pressure equal to one-half an atmosphere. 



Woolley " closes his experiences on filtration as follows: "Apparently to judge 

 from these results the causative agent of the disease ma}' or may not pass 

 through the pores of the Pasteur-Chamberland filter according to the conditions 

 surrounding the experiment." What these conditions are the author fails to 

 mention. 



Reeentty Todd ° defibrinated virulent blood by whipping, diluted it by adding 

 four times its volume of physiological salt solution (O.S per cent), and divided 

 it into two parts, part A and part B. Part A he passed through a large, close- 

 pored Berkefeld filter as slowly as possible; part B through a large and very 

 porous one as rapidly as he could. Filtration was carried out by suction from 

 an ordinary laboratory water pump and the difference of pressure was less than 

 one atmosphere. 



Fifty cubic centimeters of each of these filtrates injected under the skin of 

 cattle proved to be entirely harmless. Three control animals which were in- 

 oculated with one-fifth cubic centimeter of the same blood before it was filtered 

 contracted typical cattle plague. Ten days after the inoculation with the filtrates 

 he injected the same animals with 10 cubic centimeters of virulent blood; they all 

 contracted cattle plague, showing that they were not immune to the disease. 



In a second experiment, Todd introduced 40 cubic centimeters of citrated viru- 

 lent blood into the interior chamber of a sterilized Chamberland filter marked F. 

 After carefully closing the open end of the filter, he placed it in the peritoneal 

 cavity of an animal from Cyprus. It remained well. Thirteen days later he 

 inoculated the animal with virulent blood, it contracted cattle plague and died 

 eight days later. 



In closing his report Todd says: "Reviewing the work which has been published 

 on this question and the results of the experiments cited above, one is led to 

 the conclusion that there is insufficient evidence in favor of the active agent of 

 cattle plague being capable of passing through a filter. 



It will be seen from the foregoing that there is a wide discrepancy in 

 the results of the different workers. Semmer, Nencki, Sieher and Wyzni- 

 kiewicz, Kolle and Turner, and Todd agree that the virus of cattle 

 plague will not pass any ordinary germ-proof filter. Memmo, Martoglio 

 and Adani find that it passes through the Berkefeld filter but not through 

 the Chamberland. Nicolle and Adil-Bejr, as well as Yersin, state that it 

 passes the Berkefeld and the Chamberland marked F, but is arrested 

 by the Chamberland B. According to Woolley the virus may or may not 

 pass the the pores of the Pasteur-Chamberland filter. Although there 

 are wide discrepancies in the results reached by these authors, the dis- 

 tinctions are perhaps not greater than the differences in the methods 

 employed by them. 



'Ann. d'lg, Sper. (1904), 14, 291. 

 *This Journal (1900), 1, 582. 

 'J. of Hyg. (1907), 7, 570. 



