MOVING PHOTOMICROGRAPHY— KAZEEPF 33 1 



After haemolysis no stroma can be detected, and observations disagree 

 regarding its presence. Thus in the preparation of the blood of the 

 hen containing Spirochaeta gallinarum, or blood of the rat infected 

 with Spirochaeta duttoni, the colorless, haemolized globules frequently 

 contain perfectly motile Spirochaetes which seem to be caught in a 

 trap (pi. 8, fig. 2) and which are unable to find the opening at which they 

 penetrated. This indicates that there was a membrane at the time, 

 and an opening, and that the stroma must be very loose if it does exist. 

 As may be judged from these few pictures, Dr. Comandon's films 

 are extremely clever. They have excited the enthusiasm of scholars 

 in the congresses and scientific societies where they have been pre- 

 sented. They prove that moving pictures can add new and precise 

 observations to biological studies and that they can furnish irrefutable 

 records, the analysis of which furthers research, as well as projections 

 which faciUtate instruction. 



THE MEANS OF DEFENSE OF THE ORGANISM > 



When an infectious disease is raging, certain individuals perish, 

 others become sick and then recover, whUe still others are not attacked 

 by the disease. The resistance to infection is designated by the term 

 immunity. The mechanics of immunity are included among the most 

 complex problems of research studied by biologists. 



PHAGOCYTOSIS 



Metchnikoff, a student of Pasteur, made known in 1882 one of the 

 most active means for the defense of the organism against pathogenic 

 agents — phagocytosis. While observing the nutritional process of 

 amoebae, this scholar noticed that these very simple unicellular 

 organisms on arriving in contact with a food particle emit pseudopodia 

 that surround it and, after enclosing it, engulf it. A vacuole forms 

 about the particle thus ingested; a true digestion proceeds; at the end 

 of a variable period of time, according to the nature of the particle, it 

 disappears. A large number of amoebae feed on bacteria (pi. 10, 

 figs. 1-4). The same process is observed in other Protozoa. 



But our own organism possesses white globules, called leucocytes, 

 which, by their morphological characters, present analogies with cer- 

 tain nonpathogenic amoebae. In the healthy human organism, there 

 are 5,500,000 red blood corpuscles and 6,000 to 8,000 leucocytes to the 

 cubic millimeter. 



While observing the behavior of the leucocytes in the presence of 

 microbes introduced into the blood stream, Metchnikoff found that, 

 like amoebae, the leucocytes emitted pseudopodia, engulfed the 



« Editor's Note.— The following pages, under the general heading "The means of defense of the or- 

 ganism," which formed a separate article by Kazeefl in La Nature, No. 2975, April 15, 1936, are here reprinted 

 by permission to show the type of research that is aided by the new development of moving photomicrog- 

 raphy and its great importance to human welfare. 



