318 Journal of Applied Microscopy. 



of the isomeric cresols. By the addition of 18 grams of sodium chloride to 100 cc. 

 of a half per cent, metacresol solution, the disinfecting power is considerably 

 increased. For common use this large amount of salt is not practicable. A 

 smaller amount, however, has no effect. Seybold advises the use of Hauff's 

 metacresol for the following reasons : 1. Metacresol has a considerably greater 

 disinfecting power than has phenol. 2. Metacresol is not as poisonous as 

 phenol. 3. A two per cent, water solution is clear and does not have an injuri- 

 ous action on the hands or on instruments, and the solution has very little odor. 



H. H. w. 



NEWS AND NOTES. 



A Home-made Dark Room Window. — We have recently experimented on 

 coloring ordinary glass so that it may be used in place of ruby glass in the 

 photographic dark-room of the Biological Laboratory, University of the Pacific. 

 A pane of ordinary window glass was coated on one side with a solution of 

 gelatin colored with erythrosin. The colored gelatin was allowed to run on the 

 glass as evenly as possible and dried. The erythrosin absorbs all the green 

 rays, but permits the violet rays to pass through. It is therefore necessary 

 to coat the opposite side of the glass with gelatin, colored with orange G, which 

 absorbs the blue and violet light. The gelatin surfaces were coated with varnish 

 to protect them, and the glass thus prepared forms an excellent light for develop- 

 ing plates by the daylight. rue d. fish. 



Hardening and Imbedding Delicate Objects. — For some time I have 

 made use of the following method for hardening and imbedding fragile and 

 delicate tissues and specimens. A piece of thin muslin or cheesecloth is 

 arranged in the form of a sack having a capacity three or four times as 

 large as the volume of the specimen. The object to be hardened is placed in 

 the sack and the whole may be suspended in the hardening fluid, or placed on 

 the bottom of the vessel. By taking hold of one side of the sack the object 

 may be shifted without danger of injury. I have found this method useful 

 in hardening the brain of such animals as the sparrow, cat, and sheep. In 

 hardening histological material the tissues are in no danger of being confused or 

 lost if each sack is numbered and recorded. I have in some cases carried the 

 tissue up to imbedding in paraffin very conveniently. 



e. g. burch. 

 Fargo, North Dakota, High School. 



How TO Obviate the Vibration of Centrifuges. — A few days ago I 

 changed electric power, the speed of which is uncertain, for hand power. When 

 I attempted to use the hematokrit in my office at anything approaching an 

 efficient speed, the vibrations were so violent as to disturb the occupants of the 

 building. The custodian demanded to know if I was running an air-ship. 

 Every piece of furniture, to which the machine was attachable, was tried in vain 

 and as I needed an estimation at once, the apparatus was placed upon a folded 

 towel and held by an assistant. This answered fairly well. I then clamped the 



