1895.] Dr Lazarus-Barlow, A new method, etc. 279 



Monday, 29 April, 1895. 



Mr F. Darwin, Vice-President, in the Chair. 



Mr E. T. Dixon, Trinity College, was elected a Fellow of the 

 Society. 



Mr E. J. Bles was elected an Associate. 



The following Communications were made to the Society : 



(1) Exhibition of Palophus tiaratus (a Stick-insect from 

 Mashonaland). By Dr D. Sharp. 



(2) A new method for the estimation of the Specific Gravity of 

 Tissues. By Walter S. Lazarus-Barlow, M.D., Demonstrator 

 of Pathology in the University. (From the Pathological Labora- 

 tory, Cambridge.) 



In a communication by the author to the Royal Society upon 

 the Pathology of the Oedema which accompanies Passive Con- 

 gestion published in the Philosophical Tj^ansactions of last year, 

 a method of obtaining the specific gravity of muscle is given 

 which consists of a modification of Roy's method for estimating 

 the specific gravity of blood. It was pointed out that amongst 

 the difficulties in obtaining a correct result, one of the chief 

 depends upon the fact that the glycerine with which Roy's solu- 

 tions are made up so rapidly abstracts water from the muscle 

 that after a few seconds the tissue invariably sinks in a fluid in 

 which perhaps it floated at first. A second and also important 

 difficulty was that so many pieces of muscle were necessary in 

 order to arrive at a satisfactory result that the process not only 

 took some little time but also involved considerable destruction 

 of muscle. It was in order to obviate as far as possible these 

 two difficulties that the method to be described was adopted. 



The ideal method is one which should require only one piece 

 of muscle from which no fluid should be abstracted or added 

 during the process of estimation of the specific gravity. This 

 could of course be obtained by using superposed layers of fluids 

 of diff'erent specific gravity which have no affinity for water, but 

 since the pathologist or physiologist wishes above all to deal with 

 the tissues in a state as little altered from that in which they 

 are in the body it is clear that the fluids used should be such 

 as would not damage the muscle or other tissue. 



