APPENDIX. 



THE PRESERVATION OF MATERIAL.* 



The method commonly used in the preparation of material for 

 dissecting purposes consists in first embalming the body with suitable 

 preserving fluids; afterwards filling the arteries with a colored injection 

 mass, so that they are more easily traced. The 'objects served by 

 embalming are: (1) preserving the body from decomposition for a 

 sufficient length of time to complete the dissection; (2) keeping the 

 body as nearly intact as possible; and (3) having the organs in good 

 condition for study. The point last- mentioned is an important one, 

 since much depends on having the parts of the animal in such condition 

 that they are easily and comfortably handled, and also easily observed. 

 The desired results are accomplished, first, by introducing the preserving 

 fluid through the bloodvessels, instead of by immersing the animal, as 

 was formerly the practice; secondly, by using in the preserving fluid 

 such materials as will leave the organs in a condition as near the natural 

 one as possible and at the. same time keep them moist and flexible 

 throughout dissection. 



A suitable fluid for the purpose is that recommended by Keillert for 

 the preservation of human subjects. The formula is as follows: 



Formalin 1.5 parts 



Carbolic Acid....: 2.5 " 



Glycerin 10.0 " 



Water 86.0 " 



100.0 



A convenient method of making up the fluid, especially when em- 

 balming the animals in numbers, is to prepare the mixture of formalin, 

 carbolic acid and glycerin as a stock-solution, to be diluted for use by 

 adding to each part of stock 6 parts of water. The amount required 

 varies according to the size of the animal, the flow of the fluid in the 

 vessels, the length of time during which the animal is left under the action 



*The methods here given apply only to the preservation of specimens for 

 ordinary dissection, either singly, or in numbers for a laboratory course, with a few 

 observations on the difficulties which are likely to be experienced. Especially in 

 the matter of injections, the student Who has acquired some knowledge of the 

 vascular system will be able to make complete injections of the portal system and 

 also satisfactory injections of the systemic veins, though the latter are somewhat 

 more difficult on account of the presence of valves in the vessels. Finer vascular 

 injections and injections of the lymphatic system according to the directions given 

 in the anatomical textbooks may also be suggested. 



tKeiller, W. "On the Preservation of Subjects, etc." {American Journal of 

 Anatomy), Vol. II., 1902-3. 



