OSLER'S OBSERVATIONS. 33 



often, perhaps, clear spaces or vacuoles are to be seen 

 in their protoplasm. 



The red corpuscles in this preparation may be dis- 

 regarded, for they show no trace of amoeboid move- 

 ment, but only become slightly eremite, owing to 

 the action of the salt solution. The slight shaking 

 movement which many of them exhibit is the mole- 

 cular or Brownian movement common to all minute 

 solid particles floating in a liquid. 



The changes which the colonies of discoid particles 

 (see p. 29) undergo under the present conditions i.e., 

 dilution of the blood with salt solution and warmth 

 should be carefully studied. As a rule, the larger the 

 colony the more actively the changes, about to be de- 

 scribed, take place. If there are none to be seen in the 

 blood from the finger, a drop may be obtained from some 

 other source and prepared in a similar way. They are 

 common in the blood of some animals e.g., the rat and 

 are generally large and numerous in that of persons who 

 have been long ill. 



The masses in question (Fig. 8, a) are often of consider- 

 able size, many times larger than a pale blood-corpuscle. 

 As Osier has shown, the particles which compose them 

 are free in the circulating blood, and only run together 

 when the blood is drawn. 



Changes seen in one of the masses or colonies of discoid particles from a 

 drop of human blood, diluted "with salt solution and warmed After Osier. 



About half an hour after the preparation has been made 

 the masses may be seen to have no longer an even, toler- 

 ably well-defined contour, but to be bristling with exces- 

 sive minute filamentous projections, each of which has 

 grown out from one of the minute discoid particles at the 



