Waarom Vond van Leeuwenhoek Geen Navolging?

Title translated

Why did Leeuwenhoek not find a following?

The author's answer:

1. He kept his best lenses a secret.
2. He kept his lens grinding technique a secret. We can hardly blame him for this. Secrecy was pretty much common practice at the time.
3. He was unsystematic in his research. He did not set up or prepare a general theory of microbiology, nor did he build a system of various forms.
4. His writings were completely unsystematic; his finds were scattered among descriptions of entirely different things.

Only the second one has any validity, in my opinion.