SiGERSON — On Heat as a Factor in Vital Action. 3 



changes of plane might account for some of this, and might be a source 

 of error, I pushed my inquiries further — though here, I may observe, 

 that if such change of plane were remarked when taking place in living 

 matter, they would run a risk of being called \'ital movement. 



To represent the consistency of the amoebae a somewhat viscid body 

 is requisite, say an oleaginous fluid. By bringing drops of this into 

 contact with a heated fluid, at various temperatures, I found that — 

 1st, when the subjacent fluid was cold no motion took place; 2nd, 

 when it was very hot, no movement occurred. 



3rd. There is a stage, differing for different substance, at which 

 rapid movement is given to the globule. At this stage, certain alter- 

 ations in the colour of parts seem to mark a change in density, then 

 various alterations of form occur. Thus the globule may alter into a 

 ring, this globule divide at one portion or at several portions of its cir- 

 cumference, and re-form rapidly into globules, and these changes may 

 proceed for some moments ; then they will cease. That this stoppage 

 is due to some acquired tolerance of the heat, is shown by the fact 

 that a new di-op will undergo similar changes at this temperature. 



If the temperature be lower, the motions will be slower. Some- 

 times no eversion may take place ; then we may note simply various 

 protrusions from different parts of the periphery, and the globule may 

 change its rounded to an angular form. To accomplish these changes, 

 there must of course be transference of particles, and some of these may 

 at times be noticed passing their neighbours. 



There is sometimes a movement of the globules from one part of 

 the surface of the fluid to another; thus the first contact of the heated 

 fluid occasionally scatters its component parts in all directions. 



In such cases as these, it is manifest that the alterations, transfor- 

 mations, and changes of locality as well as of shape, are due to the con- 

 version of heat into a motor- force acting through the physical basis of 

 the viscid globule. The acquired tolerance of external influences is not 

 unknown in vital matter. 



The description which Dr. Beale gives of the movements in a 

 mucus corpuscle, applies to the non-vital movements, to a considerable 

 extent. "No language could convey," he remarks, " a correct idea of 

 the changes which may be seen to take place in the form of the 

 living mucus or blood corpuscle : every part of the substance of a corpuscle 

 exhibits distinct alterations within a few seconds. The material 

 which was in one part may move to another part. Xot only does the 

 position of component particles alter with respect to one another, but it 

 never remains the same : there is no alternation of movements. "Were 

 it possible to take hundreds of photographs, at the briefest intervals, no 

 two would be exactly alike, nor would they exhibit different gradations 

 of the same change ; nor is it possible to represent the movements with 

 any degree of accuracy, because the outline is changing in many parts 

 at the same moment. I have seen an entire corpuscle move onwards 

 in one definite direction for a distance equal to its own length or 

 more. Protrusions would occur principally at one end, and the general 



