ANTI-ENZYME IMMUNITY 233 



any of the various toxins produced by different types of CI. welchii. 

 No increased diffusion was caused by two samples of CI. histolyticum 

 toxin or by cultures of CI. tetani. 



2. Enzymic Nature of the Permeability Factor and the 

 Nature of the Substrate 



Hoffmann and Duran-Reynals (1931) reported that the perme- 

 ability factor was destroyed by heating at 60°C. for 30 minutes, 

 and also that 5X10~^ microgram represented an effective permeability 

 dose (McClean, 1936). These facts would suggest that the substance 

 acts as an enzyme. 



Meyer and Palmer (1936) reported that vitreous humor and umbili- 

 cal cord contain a mucopolysaccharide consisting of N-acetylglu- 

 cosamine and glucuronic acid in equimolecular concentrations. A 

 chemically similar and serologically inactive mucopolysaccharide 

 was likewise isolated from the mucoid phase of Group A hemolytic 

 streptococci (Kendall, Heidelberger and Dawson, 1939), from syno- 

 vial fluid (Meyer, Smyth and Dawson, 1939), and from fowl sarcoma* 

 (Kabat, 1939). This carbohydrate was named hyaluronic acid by its 

 discoverers. 



Meyer, Dubos and Smyth (1937) reported that the autolytic sys- 

 tem of pneumococcus hydrolyzes the mucopolysaccharide from vitre- 

 ous humour, umbilical cord and streptococcus. This enzyme was 

 regarded as being the same as that responsible for the autolysis of 

 heat-killed pneumococci. 



It was left to Chain and Duthie (1939, 1940) to bridge the link be- 

 tween the enzyme hydrolyzing the mucopolysaccharide and the 

 spreading factor. They found that the testis extract is active as a 

 spreading factor in a dilution of 10~^. It contained a proteolytic 

 enzyme, but this was not responsible for the permeability effect as 

 crystalline trypsin showed no similar effect. The enzyme present in 

 the testicular extract reduced the viscosity of synovial polysaccharide 

 to 1/300 of its original value (approximately that of water). Its action 

 also caused the hydrolysis of the polysaccharide, yielding N-acetyl- 

 glucosamine and glucuronic acid, which is the same as found by 

 Meyer, et al. The testicular extract produced the same enzymatic effect 



*Pirie (1942) isolated a viscous polysaccharide from two fowl tumors that did not 

 contain hyaluronidase. 



