66 ON A PECULIAR SUBSTANCE OCCURRING ON THE HUMAN TEETH. 



Sierra Leone there is a native pustular disease called craw-craw, which 

 is a species of itch breaking into open sores, and very troublesome to 

 cure. May not the above insect be the cause of this intractable local 

 disease, in the same manner as the Acarus is of the common itch ? 

 Editor.'] 



XI. ON A PECULIAR SUBSTANCE OCCURRING ON THE HUMAN TEETH. 



By Frederick Buehlmann, Candidate of Medicine, Berne. 



IN investigating the so-termed molecules of saliva of Henle, I was struck 

 by a peculiar kind of thread-like bodies placed on a granular mass which 

 displays itself, mixed with the epithelium of the mouth, and with tartar, 

 in great abundance on the teeth. I am not aware that any one, with 

 the exception of Leuwenhoeck (Opp. omnia Lugd. Batav., 1722, 

 Tom. II, p. 40), had ever mentioned them; I was therefore induced to 

 examine them with the more attention, and discovered as follows. 



There exist on the teeth of all adults, especially on those on which 

 deposits of tartar occur, or which have a tendency to form such depo- 

 sits, forms which consist of a great number of thread-like bodies, and 

 which occur of three different kinds. 



1. There are on a granular yellow substance of circular or elongated 

 form, beautiful fibres, which sprout from this parent substance like plants 

 from a bulb. This elegant form is the rarest. I have however observed 

 it several times, and Professor Valentin has also convinced himself of 

 its existence. The vessels occur in the form of tufts, presenting the 

 most beautiful curves. 



2. The fibres appear singly, scattered and often broken amid the 

 epithelium, the tartar, and the adhering slime of the teeth. 



3. Entire masses are observed of fibres which wind irregularly, and 

 are surrounded by the yellow granular mass, which are perfectly identi- 

 cal with those described as No. 1. The first of these forms is the most 

 beautiful, and possibly the primitive. It has on its first appearance some 

 similarity with the spermatic animalcules which are sometimes observed 

 of a tuft -like form, or with certain appearances of mould in the animal 

 kingdom. The vessels have a breadth of about 0.0000 6 -8th of a Paris 

 inch, and a length, which, as will be seen from the accompanying figures, 

 is extremely variable. They possess at the basis the breadth cited above, 

 preserve this breadth till about the middle, and diminishing thence, 



