THE WOMBAT. IO5 



FORMALIN AS A GENERAL PRESERVATIVE 



FOR ANIMAL AND VEGETABLE STRUCTURES.* 



(Concluded. ) 



Methylated spirit answers, and I will give you a few prac- 

 tical examples, when you will notice the colour reappear as fresh. 

 as ever, and the blood vessels become defined with the greatest 

 fidelity. Dr. Blum, I think, was the first to publish this. 



With formalin the chlorophyll in plants is not dissolved out 

 as with alcohol, and the colour of flowers is more or less pre- 

 served ; but I have not experimented to any extent in this 

 department. I exhibit five examples to-night. 



I have noticed, as others have frequently done, that the- 

 microscopical structure of the tissues is faithfully maintained, 

 the cell contents are well preserved, and the nuclei in these 

 from 5 per cent, solutions or stronger remain distinct , also 

 they allow of staining with carmine and aniline dyes. 



Formalin mixes readily with many chemical compounds, 

 and for special work I have experimented with it in varied 

 combinations. After further work in this direction I hope to 

 give you my results. My purpose to-night is only to speak 

 of it in. a general way. 



However, as so many animal forms are invested with a 

 thick integument, I will just mention two plans I have adopted 

 with success for the sake of hastening the penetration of 

 formalin to all parts of the specimen. This object is a most 

 important one for faithful preservation of detail of structure. 

 One is to kill by immersing in glacial acetic acid for a minute 

 or two, or less, according to circumstances, and without 

 washing the acid out, place the specimen at once into 5 per 

 cent, formalin, then the next da) 7 wash the acid out with fresh 

 5 per cent, formalin. Penetration is also, of course, greatly 

 facilitated by heat ; but the strength of the solution is readily 

 weakened, on account of the formic aldehyde being driven off 

 — but, bearing this in mind, it will at times be found useful. 

 I have also used various strengths of sulphuric acid, mixed 

 with 5 per cent, formalin, for insects, etc., but, of course, not. 

 on vertebrate structure, as it would cause swelling of the- 

 tissues. Alcohol also may be used with it. 



Victorian Naturalist December, 1895. 



S. R, J. TV/mWSON, 

 SURGICAL <& MECHANICAL DENTIST, 



20*, M00RAB00L STREET, GEELONG* 



Laughing Gas, &c, administered. Teeth extracted, 2/6, 



ARTIFICIAL TEETH REDUCED TO MEET THE TIMES. 



