Volume 11

Alle de brieven van Antoni van Leeuwenhoek / uitgegeven, geïllustreerd en van aanteekeningen voorzien door een Commissie van Nederlandsche geleerden.

  • Antonie van Leeuwenhoek
Date:
1939-
Catalogue details

Licence: Public Domain Mark

Credit: Alle de brieven van Antoni van Leeuwenhoek / uitgegeven, geïllustreerd en van aanteekeningen voorzien door een Commissie van Nederlandsche geleerden. Source: Wellcome Collection.

    21/406 (page 5)
    Highly Learned Sir, Your welcome letter of the 30th of May duly reached me; I saw from it that You are not satisfied as to [my views about] the nest of flies, since you think that it is not composed of several small worms which have clustered together, but is due to a single cause1)- As the time for making such an enquiry is now approaching, I consider it my duty to inform You that certain small Caterpillars which are known to me do not move but they at once spin a cocoon, all together, in order that, as I am convinced, they may be protected from their enemies, such as ants and small birds, and even more so when they have become fully grown, after which forma¬ tion of one general cocoon each of them spins a separate cocoon, from which latter they are metamorphosed into flying creatures. If You watch them, I do not doubt but you will find that the small Caterpil¬ lars, after having obtained their food from a large caterpillar up to the adult stage, will emerge from the Caterpillar, upon which they will all first spin a thin cocoon about themselves, and after having done so, each will spin a strong cocoon, in which latter (if cold weather follows) they will remain the whole winter. A certain medical doctor also sends me from Zeeland such a small cocoon, from which small flies have also emerged, but he intended also to send me the shrivelled Caterpillar from which they had emerged, but it had got lost. This Gentleman also is not satisfied about the reproduction of these small flies and requests my opinion about it. When I reply to his letter, I will send him no other but my above-mentioned views, and if it takes place in a different way, this is not in accordance with my expectations, because hitherto I have not discovered any creature dropping young that are not similar to their father and mother in many, if not in all respects for just as a horse cannot possibly bear rabbits, so I assume it *) L. refers to his exposition in Letter 146 of 23 May 1695 in Collected Letters, Vol. 10, pp. 261-265.