( 840 ) 
Microbiology. — “Pure cultures from a single cell, isolated under 
the mucroscope.” By Dr. 8. L. ScHovreN. (Communicated by 
Prot. E- A: Bi-0 Went). 
(Communicated in the Meeting of December 24, 1910). 
In 1899 I demonstrated at the Scientific and Medical Congress at 
Haarlem *) a method which I had discovered for isolating a single 
cell under the microscope, which method, worked out further and 
applied, appeared in 1901 in these Proceedings*) and also formed 
the subject of my dissertation*). Since then I have continued my 
experiments in this direction. In 1905 I again‘) published improve- 
ments of the method, with further applications and now, 5 years 
later, the method has again been so much improved and simplified 
in several respects that I feel a communication should no longer 
be deferred. 
While referring for particulars to my last publication, which, 
apart from the alterations about to be deseribed, may still serve as 
description, I wish here to outline the method in brief and then to 
mention the improvements. 
On a coverslip which has been smeared with a little vaseline and 
then passed through a flame, a drop of the material is placed from 
which it is desired to isolate a cell. At a distance of about 3 mm. 
opposite drops are put, in which it is desired to grow the pure 
culture. The coverslip is then placed on a moist chamber on the 
microscope stage. The left lateral wall of this chamber is provided 
with a horizontal slit, which is closed by a viscid fluid and through 
which a glass needle projects, bent at its end into a loop. By means 
of a simple mechanism the needle can turn round a support so that 
its end ean touch the lower surface of the coverslip. A mechanical 
stage renders it possible to do this in any part of the field. 
The space in the moist chamber is kept saturated with water 
vapour by a drop on the floor. The vapour condenses on the lower 
surface of the coverslip, and since the latter has heen treated with 
1) Een methode voor het maken van reinculturen, uitgaande van één onder het 
microscoop geïsoleerde cel”. Handelingen v/h. 7e Nederl. Nat. en Gen. Congres, 
gehouden te Haarlem 1899. 
2) “On pure cultures of Saprolegniaceeén”. These Proceedings March 30, 1901. 
5) Reinkulturen uit één onder het mikroskoop geïsoleerde cel. Proefschrift. 
Utrecht 1901. 
4) Reinkulturen aus einer unter dem Mikroskop isolierten Zelle. Zeitschr. ftir 
wiss. Mikr. und für mikr. Technik, Bd. XXII 1905 p. 10. 
