French Zoologist Quotes

What is the use of their unceasing mutations, if they do not change? In sum, the mutations of bacteria and viruses are merely hereditary fluctuations around a median position; a swing to the right, a swing to the left, but no final evolutionary effect.

Pierre-Paul Grassé

As an organ is exercised, circulation is more particularly directed to it and is more readily performed in it. Consequently, all its secretions and excretions increase. The more an organ is exercised, the more it is nourished.

Georges Louis Duvernoy