150 Mr. G. H. F. Nuttall. Tlie New Biological Test 



" The pear-shaped Figure of Equilibrium of a Rotating Mass of 

 Liquid." By G. H. DARWIN, F.R.S. 



" Sur la Stability de 1'Equilibre des Figures Pyriformes affectees par 

 une Masse Fluide en Rotation." By H. POINCARE, For. Mem. R.S. 



The following Papers were read : 



I. " On Skin Currents. Part II. Observations on Cats." By 

 Dr. A. D. WALLER, F.R.S. 



IT. " The New Biological Test for Blood in Relation to Zoological 

 Classification." By Dr. G. H. F. NUTTALL. Communicated 

 by Sir M. FOSTER, Sec. R.S. 



III. " Observations on the Cerebral Cortex of the Ape. Preliminary 



Communication." By A. S. F. GRUNBAUM and Professor 

 SHERRINGTON, F.R.S. 



IV. "On the Inheritance of the Mental Characters in Man." By 



Professor K. PEARSON, F.R.S. 



V. "On the Process of Hair turning White." By Professor ELIAS 

 METCHNIKOFF, For. Mem. R.S. 



"The New Biological Test for Blood in Relation to Zoological 

 Classification." By GEORGE H. F. NUTTALL, M.A., M.D., Ph.D. 

 University Lecturer in Bacteriology and Preventive Medi- 

 cine, Cambridge. Communicated by Sir M. FOSTER, K.C.B., 

 Sec. R.S. Received November 2, Read November 21, 1901. 



In recent publications which have appeared in the ' British Medical 

 Journal ' * and in the ' Journal of Hygiene ' t I have described the 

 technical methods whereby the so-called specific anti-sera may be 

 produced, and in the article in the latter journal, the reader will find 

 the literature on the subject exhaustively treated. The anti-sera 

 are produced briefly as follows : Assuming that we wish to obtain 

 an anti-serum for human blood, we inject human blood intra-perito- 

 neally into rabbits. After about five injections, given at intervals 

 of three or more days, the rabbit is bled to death, and its blood- 

 serum collected. The serum of this rabbit will be found to have 

 acquired the remarkable property of producing a precipitation im- 

 mediately on its being added in small quantity to a dilution of 



* 'Brit. Med. Journ.,' 1901 (llth May), vol. 1, p. 1141; (14th September), 

 vol. 2, p. 669. 



t ' Journ. of Hyg.,' 1901 (1st July), vol. 1, p. 367-387. 



