CERATOMYXA ACADIENSIS. 555 



living fish were brought in a " car" to the laboratory, where they were 

 kept alive in tanks supplied with running water. The study of the 

 living parasite was made during the months of August and September, 

 and all the preserved material was collected during the same period. 



For smear preparations cover glasses were prepared as follows: 

 After being cleaned in a mixture of 1 part bichromate of potash and 

 1 part concentrated sulphuric acid to 12 parts water, the cover glasses 

 were washed, first, in tap water, and then in distilled water, and stored 

 in 95% alcohol. AVhen required for use, the alcohol was burned from 

 them by passing them through the flame of an alcohol lamp. 



The bile duct of the fish was ligatured and the gall bladder removed 

 to a carefully cleaned watch glass, where it was cut open. Into a 

 pipette, freshly made from new glass tubing, a small quantity of bile 

 was drawn up and thence dropped on the cover glass. Most of the 

 bile was then sucked back into the pipette so as to leave on the cover 

 glass only a very thin film. The cover glass was then inverted and 

 allowed to drop on the fixing fluid in such a way that it was supported 

 by the surface tension of the liquid. In this manner the preparations 

 were given no opportunity to dry. This is practically the method of 

 Dofflein ('98), but in all cases the addition of blood to the gall was 

 avoided. Although the gall is at times very poor in coagulative 

 material, it is nearly always possible by using a perfectly clean cover 

 glass to get a good smear preparation. The fixing fluids employed 

 were (1) Schaudinn's fluid, consisting of two parts saturated aqueous 

 solution of corrosive sublimate to one part absolute alcohol, used 

 either hot or cold, and (2) Hermann's fluid, consisting of 75 cc. of 1% 

 platinic chloride, 4 cc. of 2% osmic acid and 1 cc. of glacial acetic acid. 

 These fluids were allowed to act for from five to ten minutes, and the 

 cover glasses were then transferred (after Schaudinn's fluid) to 60% 

 alcohol containing iodine, or . (after Hermann's fluid) to distilled 

 water. 



The stains used w^ere Giemsa's azur-eosin or Delafield's haematoxy- 

 lin. Both were diluted before use to one or two per cent, and allowed 

 to act for from twenty-four to forty-eight hours. After staining in 

 Giemsa's mixture, the smears were washed in tap water and destained 

 in a mixture containing 95% acetone and 5 per cent, xylol. When 

 sufficiently destained, they were passed in succession through the fol- 

 lowing mixtures: (1) acetone 70 cc. and xylol 30 cc, (2) acetone 50 cc. 

 and xylol 50 cc; (3) pure xylol, and were finally mounted in Canada 

 balsam. For the details of this method of using Giemsa's stain, 

 Kisskalt und Hartmann (:10, p. 14) may be consulted. After stain- 



