1897] MICROSCOriCAL JOURNAL. 283 



ing- like diatoms is seen which is most likely Melosira 

 sulcata though the diatoms are in a stage that their spe- 

 cific nature cannot be made out clearly. There is also 

 the Coscinodiscus, a cast of aTriceratium but the species 

 is in distiuguishableas the cast is opaque, lignite or pyrite. 

 There is also a silicious shell of Stephonopyxis turris. 

 The Triccratium looks like a cast of T. undulatum and 

 perhaps should be placed there. Sometimes the change 

 has taken place in the sileceous shells themselves. In 

 that case the casts look like diatoms. Instead of being- 

 transparent they are made up of dark substance, lignite 

 or pyrite, and the cavity with the lorica is not marked 

 at all. 



As Bacillaria are in the London clay and it is marine 

 also we can carry the Bacillaria down to the lower Eocene 

 in Geologic time. 



Notes on Formalin. 



By GEO. S. LIGGETT, M. D., 



OSWEGO, KANS. 



Every microscopist should have some formalin on his 

 work-table, especially the physician who uses a micro- 

 scope. It will preserve specimens indefinitely and will 

 harden a specimen so that an expert can make sections 

 without any other preparation. I believe it will ])rove 

 to be the most excellent preservative we have ever had. 

 There is much to learn a1)0ut it however. 



Over a year ago I had a case of acute Hematuria. The 

 urine seemed all blood. I had an eight-ounce specimen. 

 After examining it and in order to keep it from decay I 

 added some formalin. Next day I was surprised to find 

 it coagulated. It has remained in that condition ever 

 since. The bottle is nearly filled with a soft and dirty 

 greyish coagula. In the bottom there is about an inch 

 of a very hard, ^nd dark coagula. Examination of it now 



