BY DR. BURDON-SANDERSON. 189 



tity of blood operated on within the limits of temperature 

 above mentioned. 



13. Action of Electricity. The effects both of shocks of 

 friction al electricit} r ami of induced currents have been de- 

 scribed in the histological part. To what is there stated, it 

 may be added, as regards induced currents, that the most 

 marked effects are produced when the current is most analo- 

 gous in its characters to a discharge of statical electricity, and, 

 consequently, that the direct induced current 'which accompa- 

 nies the opening of the primary current is more effectual than 

 in the inverse one. In the results observed, it is important to 

 distinguish between the direct action of the shock or shocks 

 on the corpuscles, and the electrolytic action indicated by the 

 liberation of gases at the tinfoil points (see Fig. 194). In so 

 far as electroh'sis occurs, the results may be in part attributed 

 to the development of acid reaction at the positive pole, con- 

 sequent on the decomposition of the salts of the blood. A dis- 

 tinction ought also to be drawn between those effects which 

 are only produced when the corpuscles are in a living state, 

 and those which are manifested also in dead blood. The 

 discharge of the coloring matter from the corpuscles is a phe- 

 nomenon of the latter class, but there are other effects which 

 manifest themselves only when the blood employed still retains 

 its vital properties. 



14. Action of Water on the Blood. The mode of action 

 of water on the corpuscles is fully described in Chapter I. The 

 coloring matter is entirely discharged, and probably the greater 

 part of the globulin. That the whole is not expelled seems 

 evident from an old experiment, made more than twenty-five 

 years ago by Dr. Buchanan, of Glasgow, who observed that 

 .the solid residue left behind, even when repeatedly washed 

 with distilled water, still retained the power of determining 

 coagulation in serous effusion-liquids, when added to them in 

 small quantity. Again, when blood which has been acted on 

 by water is subjected to a stream of carbonic acid gas, the 

 stromata of the corpuscles show changes which indicate that 

 they still retain a substance precipitable by that gas. 



15. Action of Crystallized Ox-bile. On the addition of 

 a dilute solution of" bile crystals," i. e.. crystals of glyco-cho- 

 late and tauro-cholate of soda to blood, a great number of the 

 corpuscles are dissolved, so that the blood becomes distinctly 

 laky; and if it is derived from a suitable source, and not too 

 much diluted, the coloring matter crystallizes. On this fact 

 one of the numerous methods of obtaining hffim agio bin is 

 founded. With reference to the mode of obtaining " bile 

 crystals," see Chap. XXXYI. 



16. Preparation of Haemoglobin. Any method by which 

 the coloring matter can be caused to quit the corpuscles without 



