45 



Meeting held in the Municipal Buildings, March 24th, 1890, Professor 

 de Burgh Birch, M.D., CM., F.E.S.E., in the chair. 



THE SPECIFIC GRAVITY OF BLOOD. 

 E. LLOYD JONES, M.B., CM. I 



Blood consists of plasma and corpuscles, the former has a specific 

 gravity of about 1'025, and the latter of about TSOO, hence, when the 

 sjiecific gi-avity of the blood of a living individual has been determined 

 an accurate judgment can be formed of the proportions of these 

 ingredients in the specimen. The older methods of determining the 

 specific gravity of blood all necessitated a relatively copious supply, 

 whereas the method shown which was first the idea of Professor Roy, 

 of Cambridge (though not practically worked out by him), but has been 

 built up and modified by Mr. Jones, that now one can determine the 

 exact specific gravity very accurately without shedding more than a 

 minute drop, and is one of the most reliable methods of examining 

 and ascertaining the condition of blood known, and at the same time 

 the most rapid. Several experiments were made in demonstration of 

 the method, which is briefly as follows : — The back of the middle finger, 

 a little beyond the nail, was pricked with a fine needle — an operation 

 without any appreciable pain — which is followed by a small drop of 

 blood. This is drawn up into a glass tube or pipette. It is then blown 

 into fluids of varying standards of gravity, and when in these fluids the 

 blood rises or sinks according as it is lighter or heavier. An account 

 was then given of the influences which alter the specific gravity of 

 blood — namely : age, .sex, food and drink, alcohol, sleep, exercise, season, 

 race, temperament, &c. It also varies widely in diff'erent parts of the 

 body, and is afiected by emotions and mental states. " Blood is thicker 

 than water," says the proverb ; but how much thicker depends upon 

 all the influences named above. The healthiest condition of blood is 

 that in which the specific gravity is neither too high or yet too low, 

 but of the average, and is least susceptible to change as the result of 

 the influences given. 



The President highly complimented Mr. Jones on the importance 

 of his research, and spoke of the old methods, when bleeding was in 

 vogue, of testing the condition of human blood. He said the subject 

 was a very difllcult one, and showed how earnest had been the deter- 

 mination to grapple with it and to obtain such excellent results. 



Meeting held in the Municipal Buildings, March 31st, 1890, F. W. 

 Branson, F.I.C. F.C.S., in the chair. 



BACTERIA IN RELATION TO THEIR CONDITION OF LIFE. 



PROFESSOR E. H. JACOB, M.D. ' 



Bacteria may be divided into three forms or classes — (1) inert, of 

 which there are a large quantity ; (2) useful, as in the ripening of 

 cheese, brewing (fermentation) of beer, wine, &c., making leaf mould, 



