APPENDIX. 429 



carmine solutions. One of the most convenient and efficient inject- 

 ing fluids is 



Soluble Berlin blue ( Griibler) 3 gm. 



Distilled water 600 c.c. 



This fluid runs well, does not extra vasate, and may be used cold ; 

 perfectly fresh animals, immediately after killing, are the most favor- 

 able subjects for the manipulation. A smoothly-working hand- 

 syringe (200-300 c.c. capacity), with appropriate stop-cock and can- 

 ulae, is the best instrument, since the educated hand of the operator 

 forms the best judge of the amount of pressure that may safely be 

 applied. When the injection is completed the vessels should be 

 ligated and the tissue placed in 70 per cent, alcohol or M tiller's fluid 

 for fixation and subsequent hardening. In the case of the lungs, 

 after injecting the blood-vessels, the tissue should be moderately dis- 

 tended by forcing the preserving fluid into the organ through the 

 air-tubes. 



In conclusion, it may be repeated that the object in appending 

 these pages treating of microscopic technology is to present in detail 

 a few methods which will be found satisfactory and thoroughly trust- 

 worthy for the great majority of histological investigations. The 

 student is urged to persevere with those here given until he has re- 

 peatedly carried the manipulations to a successful issue by producing 

 the really beautiful results of which these methods are capable. 



