28 THE MICROSCOPE. 



death of the cell, for on its replacement by an indifferent fluid, the 

 movement may be perfectly re-established and continued indefinite- 

 ly." These phenomena seem equally true of cells observed /// situ 

 and of these scraped from their place and teased apart. 



The white blood cells were examined, not only when removed 

 from the vessels, but also in the vessels of the tongue, mesentery 

 and bladder of the frog. If the white corpuscles, while being ex- 

 amined in the glass slide, be irrigated with a yj^g- solution, amoeboid 

 movements ceases almost instantly, and very soon the protoplasm 

 breaks up into larger and smaller strongly refractive granules or 

 globules, and a finely translucent substance which retains the form 

 of the shrunken cell. The nucleus is more or less jagged in its out- 

 line. With weaker solutions the same phenomena are to be 

 observed, but they are developed much more slowly. 



If those which have been treated with weak solutions, and 

 whose movements have been stopped, are washed clean with a 

 neutral solution, the movements will usually return. 



If a freshly exposed bladder be irrigated with a solution -^^^ to 

 yJ-^, it soon becomes cloudy, and stasis will occur almost immedi- 

 ately in the capillaries, gradually extending to the smaller and 

 larger veins and arteries. The red blood cells lo.se their 

 symmetrical form, becoming permanently cut and curved and oc- 

 casionally swollen. Sometimes they will cling closely to the sides 

 of the vessel. To these, others are joined in little heaps, thus partly 

 blocking up the tubes, or, instead of being thus piled up, the red 

 cells may lie along the wall, side by side, in a single or double layer, 

 thus making a cylindrical investment around the blood current, 

 which still flows but with impaired velocity. Gradually, however, 

 more and more accumulation takes place, until, finally, the current is 

 stopped. Thus thrombi and emboli are formed partly, as is evident 

 by changes in the red blood cells. The white cells under these cir- 

 cumstances do not collect in the peripheral zone of the current, but 

 are mingled indiscriminately with the red ones. They invariably 

 retain their round form. This condition, which has been 

 called, "globular stasis," does not undergo resolution, if far ad- 

 vanced. 



With solutions of -g^J-g- to -j^j-g- there seems to be no tendency to 

 stasis or thrombosis. If a solution of ^^^^ be used, there is a slight 

 dilatation of both arteries and veins, which seems permanent so long 



