SIZE, SHAPE, AND HYDRATION OF VIRUSES 



51 



140 A. It is truly remarkable that so difficult a virus to study 

 should nevertheless be susceptible to correct characterization 

 by these means. 



The fourth illustration is the study of rabbit papilloma virus 

 carried out by Neurath, Cooper, Sharp, Taylor, Beard, and 



.10 1.20 



Solvent Density 



1.30 



Fig. 2.8. Buoyancy measurements by Scliachman and Lauffer (1949) 

 on TMV using two second solutes. The steep slope is for serum albumin, the 

 gentle slope for sucrose. Differential entrainment of water is suggested to 

 explain the two slopes. 



Beard (1941) and Sharp, Taylor, Beard, and Beard (1942). 

 Rabbit papilloma virus can be obtained from warts in Western 

 cottontail rabbits. The collection of material from four trapping 

 seasons gave 430 gm of wart tissue. This was ground and 

 extracted, and the virus separated by multiple centrifugation. 



