528 OPERATIONS ON THE CIECULATOEY SYSTEM. 



2d. A bsorbents. — Hemostatic absorbents proper are agents 

 which by their capUlary action suck up or soak in the sanguineous 

 element from traumatic surfaces, and having their structure 

 thickened and condensed by the presence of this contained liquid, 

 coagulated ia their mass, oppose thereby an iaviacible obstacle to 

 the escape of the blood. Oakum, charpie, punk, spider-webs, 

 flour, fuller's earth, sponge, and various vegetable powders be- 

 long to this catalogue of medicaments. Oakum, which is the 

 substance which meets with general favor and is most commonly 

 used, is applied in the form of balls, dry, or soaked in cold water, 

 and packed over or into the depth of a wound, and kept in place 

 with bandages or compresses. 



Compressed sponge has proved, in our hands, an excellent 

 hemostat, not only in capillary bleeding, but in that also of me- 

 dium-sized vessels. There is, however, an objection to its use in 

 the fact of its Hability to become adherent to the tissues with 

 which it is in contact, and the consequent danger of renewing the 

 hemorrhage when removing it. 



3d. Astringents, or Styptics. — These agents produce the co- 

 agulation of the blood, by a chemical action, resulting from the 

 combination of the astringent's substance with the Hving tissues. 

 Their action differs essentially from that of the refrigerants in 

 the fact that they possess the special property of producing, by 

 their power of fibrillar astriction, the occlusion of the vessels 

 through the coagulation of the blood in their interior. 



Astringents are used in both the soUd and the Hquid form. 

 Burnt alum in powder, and certain vegetable powders, belong to 

 the first class. The solution of sulphate of iron, sulphate of 

 copper, alum, acetate of lead, alcoholized water, solution of tannic 

 acid, etc., are included in the second. They must be judiciously 

 used, however, because of their liability sometimes to excite local 

 inflammations, more or less active. The action of the liquid as- 

 tringents is deeper, more energetic, more lasting, and more dur- 

 able than that of the soHd, and they are for that reason sometimes 

 more reliable for the control of hemorrhages from large vessels. 

 Theii- consistency renders them, of course, alone available for 

 moistening compresses, balls, the tampon, or pads of any descrip- 

 tion. The most powerful of this class is the perchloride of iron, 

 which is remarkable for its power of coagulating the blood almost 

 instantaneously. "When applied with oakum upon a bleeding sur- 



