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swarms of Bacteria, spores, &c.; if you now place it in two flasks 

 A and B, then boil both and stop up a carefully with cotton 

 wool while boiling, but leave b's mouth open, you will find 

 after a few days, that whilst a only contains the original 

 Bacteria— dead, having been killed by boiling, the flask b 

 contains the dead ones and is milky with the development of 

 fresh ones, which exhibit true vital movement. It is such 

 dead Bacteria as exist in a, which by their Brownian move- 

 ments have led to the assertion that living Bacteria develop 

 after boiling in closed vessels,] 



On a NEW Method of Studying the Capillary Circula- 

 tion in Mammals. By Dr. S. Stricker, Professor of 

 Experimental Pathology in Vienna ; and Dr. Burdon 

 Sanderson, Professor of Practical Physiology in Univer- 

 sity College, London. 



The science of physiology is based on exact observation of 

 the mechanical and chemical changes which take place in 

 living beings. For this purpose the same methods and 

 instruments must be used as are employed in physics. The 

 observations, however, are much more difficult than those 

 of the physicist, because the subject of observation is a 

 living being, and consequently the conditions are much 

 more complicated than those with which he has to deal. 

 Hence it is of the greatest importance to devise good methods 

 — so much so, that science is as much indebted to those who 

 invent them, as to those who discover new truths. 



The purpose of the method we are about to describe is 

 the observation of the Avay in which the blood streams 

 through the minutest vessels ; of the visible changes which 

 take place in the living tissues around these capillaries ; 

 and of the relation between these changes and the circula- 

 tion. The subject is full of interest and importance : — 

 first, in relation to those normal changes in the living 

 tissue which constitute nutrition ; and, secondly, in relation 

 to those modified changes Avhich constitute disease. 



Hitherto this observation has been made only in the 

 transparent parts of cold-blooded animals. The earlier 

 observers contented themselves with restraining the move- 

 ments of the animal in an imperfect manner by mechanical 

 means. More recently one of us (Prof. Stricker) introduced the 



