322 THE AMERICAN MONTHLY [Oct. 



A proximate analysis of the two layers of ooze gave 

 an average of about 25 per cent of carbonate of lime and 

 50 per cent of sand and clay for the one : and no more 

 than 10 per cent of carbonate of lime and at least 66 per 

 cent of sand and clay in the other. The most abundant 

 species are evidently Orbulina globigerina. Then come 

 Sphaeroidea, Pullenia, Biloculina, Puloulina, Anomolina, 

 and Rotalina. There are also a few diatoms and sponge 

 spicules. 



The presence of the stones would seem to prove that 

 the spot must be on the margin of the Arctic eddy, for 

 the heavy stones cannot be conceived to be dropped in- 

 to the midst of foraminiferous ooze except from melting 

 ice. The temperature observation also shows that the 

 position is near the margin of the Gulf Stream, for a 

 little further west the water was cold and there was very 

 little current. The sediment forming at such a point in 

 the bottom of the Atlantic must therefore derive its 

 material from a very extensive range of geological for- 

 mations, possibly a very considerable portion being 

 brought by glacial action ultimately from the highlands 

 of Iceland, Greenland and Labrador. 



A Method of Hermetically Sealing Cultures of Bacteria. 



By CHA-RIvES F. DAWSON, M. D., 

 Assistant iu the Division of Animal Pathology, U. S. Dept. of Agriculture. 



In the November number of the " Centralblatt fur 

 Bakteriologie und Parasitenkunde," 1892, I published a 

 preliminary note on a method for hermetically sealing 

 culture tubes. At that time I was especially desirous of 

 perfecting a seal to be used in making permanent cul- 

 tures for exhibition at the World's Fair, in Chicago, in 

 place of the clumsy and inefficient arrangements which 

 had previously been used to prevent evaporation and 

 final contamination. 



Since publishing the preliminary note, I have had op- 



