1970 



Journal of Applied Microscopy 



flat top permits the table being placed against a window, and the reagent bottles 

 may be arranged at the sides so as not to interfere with the light. A large pane 

 of window glass makes a fairly good surface upon which to place the microscope 

 and make the preparations. I use a sheet of manila paper under the glass, 

 with small squares of black and white paper at the front to aid in seeing the 

 different-colored objects when mounting them. 



The illustration shows the table with all of the features mentioned. 

 Agricultural Experiment Station, New Haven, Conn. W. E. Britton. 



Marble Blocks for Celloidin Tissues. 



The micro-chemical color reaction of tissues embedded in celloidin and 

 mounted on resinous deck-plugs or cork, suffers constant deterioration in the 

 alcohol preservative ; the deleterious action of the soluble resins renders pine 

 wood particularly in-apt for blocking celloidin-mass. Though its use is ill-advised, 

 it is still adhered to on account of availibility and cheapness. As no means yet 

 devised can restore to celloidin sections, thus affected by the resins, their pris- 

 tine color-reaction, the use of wood or cork is strictly limited to temporary 

 mounting ; at least this should be so. For permanent preservation on the block 

 nothing serves better than mosau'cuhes of domestic or Italian marble. The mosaic 

 " squares " may be had in various sizes ; three-quarters of an inch square by 

 half an inch thick run about thirty to the pound, and cost five cents ; four sur- 

 faces of the cubes are plane and unpolished and the celloidin adheres perfectly. 

 After a year's trial the author is satisfied that the marble squares possess every 

 advantage of the expensive vulcanized fiber blocks. 

 Chicago Homeopathic Medical School. Edward Clark StreETER. 



A New Colony Counter. 



From a design submitted to Bausch iv: Lomb a new bacteria colony counter 

 has been made by which greater accuracy may be attained. The value of 



the counter is in the fact 

 that the glass bearing the 

 ruled lines may be brought 

 very close to the colonies, 

 A glass disk ruled to 

 square centimeters is 

 mounted in the end of a 

 short barrel (Figs. 2 and 

 o B) that moves freely by 

 screw thread within a col- 

 lar, C. A block similar 

 to that used in the Barnes 

 dissecting microscope, but 

 of greater size, has a metal 



circle (Figs. 2 and 3, Cir.) 

 Fig. 1. — Block without disk or lens. 



