Recapitulation is a bold and influential idea that is particularly associated with Ernst Haeckel though many other biologists also supported it in the nineteenth and early twentieth centuries. According to the theory of recapitulation, the stages of an organism’s development correspond to the species’ phylogenetic history- in a phrase, “ontogeny recapitulates phylogeny.” Each stage in development corresponds to (that is, [...]
The method generally employed for the evaluation of germicides is to rate them according to their phenol coefficients. In addition to this, a number of newer methods have been proposed, which are designed to measure the toxicity of germicides for tissue as well as for the test bacteria. 1. Phenol-Coefficient Method: The phenol-coefficient test was first proposed by Rideal and [...]
Here is a list of fifteen main chemical agents that can kill infection causing organisms:- 1. Preservatives 2. Acids 3. Nitrates and Nitrites 4. Alkalies 5. Salts 6. Reducing Agents 7. Oxidizing Agents 8. Phenols and Cresols 9. Alcohols 10. Glycols 11. Dyes 12. Mercury Compounds 13. Soaps 14. Surface-active Agents and Synthetic Detergents 15. Sulfonamides. Chemical Agent # 1. [...]