1 '. I Prof. C. S. Sherrington. On Change* in the Blood 



I hare remedied by increasing the area for enumeration on the floor of the 

 counter. I hare always counted all the leucocytes found on the whole ruled Jloor- 

 rpace of the two counter*, i.e., not merely on the squares, but outside them, as far 

 as the ruled lines extended. The area thus obtained was in one of the counters 

 (Counter A) 5} that of the squared area. In the other counter (Counter B) it was 

 4}r, the sise of the squared area ; this I have treated as 5. As basis for calcula- 

 tion, I hare had, therefore, instead of the usually ascertained actual number of leuco- 

 cytes in (V01 mm. of blood, the actual number in 0*0215 mm. of blood, a basis 

 more than twice as wide. The counting has been made on the Zeiss movable stage 

 on his Stativ IV, 1, with the dry 4 mm. apochromatic objective, usually combined 

 with ocular 8. Countings hare been occasionally carried on on the warm stage 1 

 (Israel's). 



The amount of haemoglobin in the blood I measure by the Gower'a,, 

 instrument, by the light of a Welsbach lamp reflected from a vertical' 

 sheet of white paper not otherwise illuminated. 



The specific gravity of the blood is estimated by Roy's* method, 

 as in the observations by Copeman and myself .f The specific gravity 

 of the blood serum is also observed by Roy's method. The blood is 

 previously centrif aged in capillary tabes. Havilland and Lloyd JonesJ 

 have both employed the centrifuge for separating corpuscles from 

 fluid in minute quantities of blood received into capillary tubes. 



The exact procedure with me has been as follows.' A drop of blood, as it 

 exudes from a prick in the skin, is taken by capillarity into a fine, freshly drawn 

 glass tube, like a vaccine tube, but longer, and bent into a JJ shape. The capillary 

 U-tube is then placed with its bent end downwards into a "bucket" on the centri- 

 fuge, or in a radial slot on a vulcanite disc ; the two open ends will then lie toward 

 the centre of rotation, and in a few minutes a clear layer of serum or plasma is 

 obtained in each limb of the tube. The specific gravity of the supernatant fluid 

 can be readily ascertained by Roy's method. I say serum or plasma, because it 

 is surprising how often no trace of fibrin seems to exist in the clear layer, even 

 on standing for a long time. 



The clear fluid I have often found to be absolutely cell free. I 

 shall refer to the fluid as serum, but I suspect that in several instances 

 it was pure plasma. 



Where the temperature is recorded, the rectal temperature in degrees centi- 

 grade is meant. By respiratory rate is meant number of inspirations per minute. 



II. 



The varieties of haemic leucocytes which I have attempted to dis- 

 tingaish are explained more fully on pp. 186 194. The nomencla- 

 ture adopted is based on Wharton Jones and Max Schultze.|| 



' Journal of Physiology,' vol. 6, p. 9, 1884. 

 t ' Journal of Physiology,' vol. 9, p. 8, 1890. 

 J ' British Medical Journal,' September 23, 1893. 



"The Blood Corpuscle considered in its different Phases of Development," 

 ' Phil. Trans.,' 1846, p. 64. 



U ' Arcbiv fur Mikroskopische Anatomic,' vol. 1, p. 1, 1863. 



