REPARATORY INFLAMMATION IN ARTERIES. 23 



periments for this last series were made upon the femoral and 

 carotid arteries of good-sized rats. 



The various operations upon dogs were j^erformed during 

 antesthesia ; those upon rats after they had been bridled and 

 tied down to a board. The vessels containing thrombi five 

 days old and upward were generally injected with Beale's 

 Prussian blue fluid. In all cases the vessel operated upon 

 was removed immediately after the death of the animal, ex- 

 treme care being taken to avoid pressing upon or stretching 

 that portion of the vessel which contained the thrombus. Im- 

 mediately after removal from the animal the specimens were 

 usually placed in dilate alcohol, which was subsequently 

 gradually strengthened from day to day by the addition of 

 small quantities of strongest alcohol. Occasionally a specimen 

 was hardened in chromic acid or Miiller's fluid. 



The specimens were allowed to remain undisturbed in the 

 hardening agent until they had become thoroughly firm and 

 hard. 



After that they were placed for a daj- in absolute alcohol. 

 They were subsequently removed from this and saturated with 

 oil of cloves, and were then imbedded in a mixture of about 

 one part of benzine to twelve or sixteen parts of paraftine. 

 Thin sections, both longitudinal and transverse, were then made 

 from each specimen. Generally all such sections were subse- 

 quently stained with carmine, and temporarily prepared for 

 microscopic examination by being mounted whole in oil of 

 cloves, or by being torn apart by needles for examination of 

 their isolated elements. A few gold and silver preparations 

 were also made. It may be stated at this point, that the ori- 

 ginal drawings which illustrate my own part of the labors 

 chronicled in these pages are not mere diagrams, but are 

 actual copies of objects in the field of the microscope, traced 

 b}- myself, as accurately as possible, by the aid of a good 

 camera. 



