Wrote Letter L-527 of 1716-03-13 to Gottfried Leibniz about human twins, trees, birds, size of sperm, number of eggs in fishes' hard roe, structure of tendons and muscle fibres, the heart; does not want to be paid for research or to teach students

March 3, 1716
Standard reference information
Leeuwenhoek's number: 
Collected Letters number: 
Collected Letters volume: 

This letter was wrongly dated as 13 March in the Send-Brieven and its Latin translation in Epistolae Physiologicae. Its correct date comes from a letter from Joachim Georg Reinerding to Leibniz in a letter of 1716-03-07.

The rare occurrence of twins with certain animals. From the seeds of trees too, in general only one develops into a mature tree. The difference in the number of young in nidifugous and nidicolous birds. Spermatozoa from big and small animals are about the same size. The number of eggs in fishes' hard roe. Viviparous fishes produce only a few young. The structure of tendons and muscle fibres. The functioning of the heart.

Leeuwenhoek does not want to be paid for his research, nor does he want to teach students.

I have had no inclination at all to teach someone; for if I would have taught one person, then several others would have come, assuming that they had as much right to be taught, and thus I would become a slave, whereas I strive to remain free.