Physical properties of bronchial secretion.

The Weissenberg rheogoniometer is designed to estimate viscosity at a single applied 
shear. By varying this shear, the associated detailed variation of viscosity 
may be studied. The level of viscosity depends more on the 
macroscopic appearance of the sample than the disease with which it 
may be associated. This has particular significance in relation to cystic 
fibrosis. In cystic fibrosis, the sputum viscosity is not abnormally high. 
It is not higher than that of macroscopically similar sputum from 
chronic bronchitis or asthma. Whatever the feature differentiating cystic fibrosis from 
other diseases, it is not the viscosity of the sputum. 