C ) 
II. A Letter to the Royal Society, from Mr. An- 
thony Van Leeuwenhoek, F. S. Concern- 
ing the Whitenefs on the Tongue in Fevers, 
Delf^ Oftob. 18, 1707. 
? Have been long of Opinion, that our Tongue isoifuch 
a Form, that when it is found ancfof good Condition, 
it does not only communicate to the Body whatever is 
agreeable to it felf, but alfo admits one part of the Mat- 
ter that lies upon it, into the Manifold Veffels of which 
it is compofed 3 infomuch that by the Veins it’s commu- 
nicated to the Heart, and ferves for Nourifhment to 
the Body, and ftrengthening of a well Conftituted 
Tongue. 
It fo happened, that in the beginning of laft Septem- 
ber t was feized by a violent Fever, which however laft- 
ed but three days with me 5 upon the Fourth day I view- 
ed my Tongue with a Magnifying Looking-Glafs, and 
obferved, that it was all ovci covered with Whitenefs, 
only about a Fingers Breadth of the Tip was of its Na- 
tural Colour 3 this Whitenefs is judged by moft People 
to proceed out of the Stomach or Bowels, by the Swel- 
ling of the Guts, or eife from a (harp Humour out of 
the Head* 
Perceiving my Tongue thus all over White, I feraped 
off. a little with a Penknife, and placed it before a Mi- 
crofcope. and prefently judged, that thofe that call this 
White Matter in our Language Beflagentfaijt, and fo 
publifh it in their Books, are much miftaken, for that 
which truly bears that Name muft be fometfaing from 
without, and not any Matter protruded from the 
Body. Now 
