TUBIFEX. 305 



For killing and preserving, Tellyeoniczky's aceto- 

 bichromate was first used, but the tissues shrank badly in 

 this reagent. I then tried Perenyi's fluid and Bles' 

 fluid,* and these, while killing the worm very quickly, do 

 not cause the tissues to shrink. Although, later on, other 

 killing reagents were used, I found none so generally 

 satisfactory as Bles' and Perenyi's fluids. 



Zenker's fluid was used, especially for nephridia, 

 with good results. 



The staining reagents most commonly used were 

 borax carmine with picro-indigo-carmine as a counter 

 stain, and brazilin,t which is a very delicate and effective 

 stain. Iron haematoxylin was also used, and this 

 rendered the muscle fibres very distinct. 



II. Historical Survey. 



Before entering upon a description of the minute 

 anatomy of Tubifex rivulorum, which forms the subject of 

 this Memoir, it will be interesting to notice to whom we 

 are indebted for the present condition of our knowledge 

 of this form. 



As early as 1745 Bonnet referred to it, but was 

 content with describing certain peculiarities in the habits 

 and general form of the worm, and with referring to its 

 method of regeneration after artificial fission. He did not 

 attempt to give any details of its structure. Schoeffer in 

 1764 gave a figure and description of Tubifex rivulorum, 

 which he called " Kleinen Wasseraal." 



* Bles' fluid 90 parts 70% alcohol. 



7 ,, strong Formol. 



3 ,, Glacial Acetic Acid. 



t Brazilin 1 % Iron Alum in 70 % alcohol . 



0-5% Brazilin; 



