and Laboratory Methods. 1901 



of cotton. (Such apparatus may be obtained from the firm of Franz Hugershoft, 

 of Leipzig). A small high beaker is set on a Petri dish and covered with a 

 larger one ; all are cleaned and made very hot. Six such sets are prepared. 

 The solution in the flask is heated to boiling and the short tube still kept closed, 

 while the stop-cock is opened. The hot liquid is caught in the beakers, boiled 

 for a short time and covered with the large beakers. The whole remains sterile 

 for a long time, as in the case of bacteriological Petri dishes, and each glass 

 contains fronl 40 to 50 c. c. of salt solution. 



To study the living blood of a frog the animal is carefully wiped off, the skin 

 cut through on the foot joint, and drawn back as far as possible on the lower leg 

 and the joint is cut through with a scissors snip. The bleeding stump is washed 

 off in sterile .8 per cent, salt solution and rinsed vigorously in the six prepared 

 beakers of 8 per cent, solution. They are immediately covered. The liquid is 

 allowed to settle and some of the sediment is taken up in a recently made, clean 

 capillary glass tube. This is placed on the specially cleaned and sterilized slides 

 and covered with similarly prepared covers. The author realizes that the process 

 appears very laborious, but after once being done is not really so bad. The 

 results are excellent. 



B. Fixation and staining. The author uses 3-1 or 9-1 osmic-acetic (3 or 9 

 vols, of 2 per cent, osmic acid with 1 vol. of 6 per cent, acetic acid, containing 

 y% per cent, methylen blue.) A trace of acid fuchsin may be added. With inver- 

 tebrates a trace of acetic acid sometimes produces an objectionable precipitate of 

 granular albumen. Then osmic acid alone is used. Acetic acid has the objec- 

 tion that it decolorizes hemaglobin ; with osmic acid this may with care be pre- 

 vented. Not only must this decolorizing be prevented, but also certain funda- 

 mental changes of the stroma into a hyaline substance. Osmic-acetic (9-1) 

 cooled on ice is peculiarly favorable to the demonstration of blood plates in the 

 blood of man or mammals. The pricked finger or ear of a rabbit cut at the tip 

 is vigorously stirred in the cold osmic-acetic. a. m. c. 



Argutinsky, J. Zur Kenntniss der Blutpliitt- This author working on malarial para- 

 Chen. Anat. Anz. 19 : 552-554, 1901. ^j^gg g^^s blood-plates to be nucleated 



bodies, as has been found by Deetjen, Dekhuyzen and Kopsch. He 

 emphasizes the interesting researches of Nocht, who uses eosin-soda-methylen 

 blue for differentiating malarial blood preparations. This stain was made by 

 mixing 2-3 drops of a one per cent, eosin solution with 1-2 c. c. of water ; to 

 this is added drop by drop a solution made of one per cent, methylen blue with 

 a half per cent, of soda ; this liquid has stood for several days in a paraffin oven 

 at 50°-60° and has been cooled. This addition is continued until the color be- 

 comes so dark that the eosin can hardly be seen. A preparation stained for 5-10 

 minutes, shows no precipitate and gives excellent nuclear stains. Such an alka- 

 line stain quickly spoils, but that made naturally by the "alkaline methylen blue" 

 lasts longer. The red stain thus made is called by Nocht the " red of methylen 

 blue." Using the red derivative of methylen blue a very sharp chromatin stain 

 is surely gained in malarial parasites and white blood cells. If a very thin 

 malarial blood smear preparation, carefully fixed in sublimate alcohol, is stained 



