APPENDIX 97 



DISSECTIONS. All dissections of small animals should 

 be made in pans under water. The different specimens 

 may be pinned out on the paraffin with ribbon pins. If 

 the student is working on fresh specimens, and is not able 

 to finish them in one day and wishes to keep them fresh, 

 add several drops of carbolic acid to the water. 



INJECTIONS. Blood vascular and water vascular systems 

 are more easily studied, if injected with a colored solution. 

 The following solution is a good one: One part gelatin 

 to four parts of water. Soak the gelatin thoroughly in 

 the water, and add one part of a saturated solution of 

 acetate of lead in water, and one part of a saturated solu- 

 tion of potassium bichromate. These are best mixed while 

 hot, because the gelatin is then liquid. Filter the whole, 

 hot, and inject the specimen while the mixture is warm. 

 A syringe is necessary for the injection. Attach a piece of 

 glass tubing drawn to a point to the end of the syringe by 

 a rubber tube. There should be a constriction near the 

 point of the glass tube, to afford an opportunity to tie an 

 artery or vein to it. Several pieces of tubing should be 

 made with different sized points to fit various sized organs. 

 By removing the syringe, the remaining part of the appara- 

 tus will serve admirably to inflate the lungs, alimentary 

 canal, etc., of the animals studied. 



PRESERVING SPECIMENS. Ordinary specimens may be 

 preserved for museum use in 85 % alcohol. Some may be 

 well preserved in 4 % formalin. Certain preparations of 

 the different organs of the body made during the progress 

 of the work may be preserved in Fischer's solution. It is 

 made as follows: 50 cc. of formalin, 15 g. of zinc 

 chloride, 100 g. of sodium chloride (common salt), and 

 2000 cc. of water. Mix them until dissolved. 



HERRICK LAB. EX. 7 



