192 



Scientific Proceedings (76). 



Chickens Nos. 3a and 4 had been inoculated with serum B and 

 white bone marrow before, but not chicken No. 6. The same re- 

 sults were attained in experiments IV, V, VI, VIII, and X. All 

 chickens which were treated with attenuated serum did not die 

 when inoculated with a 2d or 3d dose of attenuated serum. All 

 chickens which were not treated succumbed to the first doses of 

 attenuated virus when it was kept only 2 or 3 days' time in tissue 

 culture of white bone marrow. Always controlling experiments 

 with the same untreated serum kept on ice were started, which 

 killed the animals in due time. 



It is possible to keep virulent the living agents of cyanolophia 

 in plasma alone at a temperature of 38 0 for six days and 

 longer, but the same virus dies in plasma, in which living 

 white bone marrow is kept, in six days (experiment IX). 

 The controlling experiment with serum, which was kept on ice, 

 was positive, so it is true that the virulence of living agents of 

 cyanolophia will be attenuated, and later die through the activity 

 of the leucocytes. It was possible to shorten the length of time 

 in which virulent serum was kept in tissue cultures of white bone 

 marrow, and still inoculate it without success when the treated 

 animals were used again. Animals 3a, 4, 7 and 8 survived after 

 inoculation with serum Mi which had been only 2 days in tissue 

 culture (Experiment VI). Serum Mi killed chicken Mj after 

 it was kept 5 days on ice, in due time. A shortening of the at- 

 tenuation period to twenty-four hours was not sufficient to weaken 

 the serum M 2 . Chicken 7, which again was used, died in forty- 

 eight hours, after having veen inoculated with serum Mi, that 

 had only been one day in plasma and white bone marrow. 



Steinhardt and Lambert 1 cultivated the living agents of vac- 

 cinia in tissue cultures of rabbit cornea. They report a definite 

 increase of the virus, as measured by the effects of successful 

 reinoculations. Growth of the virus could be observed in tissue 

 cultures of the rabbit's cornea only, while heart, kidney and 

 liver gave no results. My experiments, previously reported, 

 prove a rapid attenuation of the virus in white bone marrow tissue 



1 Steinhardt, E., and Lambert, R. A., "Studies on the Cultivation of the Virus 

 of Vaccinia, II," Journ. of Inf. Diseases, 1914, Vol. 14, pp. 87-92. 



