STAINING WITH BKAZILIN. 471 



were equally well defined in the two preparations ; but the 

 iron-brazilin showed an advantage in that the spermatozoa 

 were triple stained, the head, middle piece, and tail being 

 clearly of dil?ei-ent colours. 



A preparation of the sciatic nerve of a dog stained in 

 brazilin exhibits the neurokeratin remarkably clearly, but 

 the axis-cylinder is not well stained. 



Our method has great advantages in showing the blood- 

 supply of an organ, the red blood-corpuscles being stained 

 very deeply. Preparations of ovary of a cat and kidney of a 

 dog exhibit the capillary plexus excellently. 



It is, howevei", principally in cytological work I think that 

 the neAv method will be valuable, as we have found after 

 many experiments, in our investigations on the very delicate 

 nuclear structures of the Suctorian Dendrocometes, that 

 it gives us by far the best general results. 



It is obvious that a good deal more must be done before an 

 opinion can be expi'essed as to the general value of this 

 method, but I have thought it right to bring it before the 

 notice of workers in various branches of microscopic science 

 at the present time, because I feel that it is a method well 

 worthy of further trial. 



In conclusion I may say that the somewhat severe test of 

 exposing slides to the action of direct sunlight for several 

 mouths has not indicated any appreciable fading effect. 



I am indebted to Professor W. H. Perkin, juu., F.R.S., for 

 much valuable advice and assistance in working out this 

 method. 



