1895.] NATURAL SCIENCES OF PHILADELPHIA. 39 



specimens is illustrated by six photomicrographs of human blood in 

 the different forms which it assumes upon the warm stages. 



The method of study is illustrated by the following series : — 



Series A. — The amoeboid motion of the white blood corpuscle. 

 The change of shape and motion with relation to the surrounding 

 stationary and identical fields is well marked. 



Series B. — This series shows the power of the white blood cor- 

 puscle in forcing its way through a mass of red crenated and ad- 

 herent blood corpuscles. 



Series C. — Is of marked interest; a white corpuscle has seized 

 upon a red corpuscle and a series of photomicrographs shows that it 

 has dragged it through a considerable distance in a field which is 

 proved to be stationary and identical in all the photomicrographs. 



Series D. — This series shows motion in a red blood corpuscle, 

 situated in a field in which the series proves no other motion took 

 place during one half hour. This motion must, therefore, have been 

 produced by some inherent power in the red blood corpuscle, and as 

 the photomicrographs show that no twist has occurred, the motion 

 cannot be due to a previous torsion, and may therefore be considered 

 a truly amoeboid motion of the red blood corpuscle. 



Series E. and F. — Show the diapedesis of the red blood corpuscle 

 from a capillary in which the blood is in motion and from one in 

 which there is stasis of the blood. This phenomenon, therefore, 

 occurs under two opposite or nearly opposite conditions as regards 

 intra-vascular blood pressure, indicating, perhaps, that diapedesis 

 is not a filtration due to pressure, but is due to the amoeboid 

 motion and power of the red blood corpuscles. 



Series G. — -This series shows an empty capillary. Along the in- 

 ner surface of its wall may be seen white corpuscles, in which the 

 series indicates movement. The diapedesis of two red blood cor- 

 puscles from this empty capillary tends to strengthen the belief in 

 the amoeboid motion of the red blood corpuscle. 



Further photomicrographs illustrate the position of the corpuscles 

 within the capillaries, and show the presence of nuclei in the red 

 corpuscles of the frog while in the living tissues. Different forms of 

 the malarial plasmodia, and the application of the method to path- 

 ological studies are illustrated by other photomicrographs. 



The pictures are not shown as the perfect results of this method, 

 or as the outcome of research by it. They are simply to illus- 

 trate the author's method of studying cell motion. Inferences based 

 on the pictures are foreign to the purpose of the communication, 

 which is intended merely to demonstrate a method of study worthy of 

 scientific consideration. Its usefulness in producing accurate illus- 

 trations, both for publication and for lantern slides, cannot be over- 

 estimated, as it supplies pictures whose counterpart can be found 

 under the microscope. 



