576 SUMMARY OF CURRENT RESEARCHES RELATING TO 



plasinic granulations which play an important part in the formation 

 of the cellular plate, and of which M. Degagny makes no montion. 

 The figured element must not be confounded with the amorphous 

 nuclear fluid ; methylcne-blue is not a suitablo substance for dif- 

 ferentiating the elements which enter into the constitution of tho 

 nucleus or of the cell. 



New Element in the Blood.* — After giving his own observations 

 on the " new element " of tho blood, for which ho adopts the namo 

 plaque, Mr. G. T. Kemp gives an historical review of tho literature* 

 on the subject, and the theories as to tho origin aud function of these 

 plaques. He describes their histology and micro-chemistry, and 

 concludes with a bibliography of the subject. 



The results of his own and other observations he summarizes in 

 tho following words : — 



1. In addition to the red corpuscles and leucocytes, the blood 

 normally contains a third histological element, the plaques. 



2. Although strong resemblances exist between the plaques and 

 the other histological elements of the blood, there is not yet sufficient 

 evidence to establish a genetic connection. We are therefore obliged, 

 for the present at least, to regard the plaques as independent 

 elements. 



3. When the blood is drawn the plaques break down almost 

 immediately. This is not true of any other element in the blood. 



4. The breaking down of the plaques is intimately connected, in 

 its time-relations at least, with the clotting of the blood. 



5. The connection between the breaking down of the plaques and 

 the coagulation of the blood is not histological, but chemical, i. e. the 

 plaques appear to give a soluble substance which is active in 

 coagulation. 



6. The active agent in question is most probably fibrin-ferment. 



7. Fibrin is deposited histologically independent of any of tho 

 cellular elements of the blood. 



8. When the clot is very scant, fibrin is deposited as long, needle- 

 shaped, crystal-like bodies. 



Histology of Central Nervous System.f — Prof. H. Gierke com- 

 municates the first portion of a research on the histology of the 

 central nervous system, which consists of a detailed account of the 

 supporting substance ("Stiitzsubstanz") in which the nervous elements 

 are embraced. His results are based on a study of numerous types 

 from fishes upwards to man. 



I. Technical Methods. — (a) For the indispensable isolation process 

 Dr. Gierke recommends extremely dilute chromic acid and salts, 

 Eanvier's " alcohol a tiers," but especially a solution discovered by 

 Landois, consisting of (1) neutral chromate of ammonia, 5 gr. ; (2) 

 phosphate of potassium, 5 gr. ; (3) sulphate of soda, 5 gr. ; (4) dis- 

 tilled water, 100 gr. (b) For staining, he found carmine by far the 

 most effective colouring substance, in the common associations with 



* Stud. Biol. Laborat. Johns-Hopkins Univ., iii. (1886) pp. 294-339 (1 pi.), 

 t Arch. f. Mikr. Anat., xxv. (1885) pp. 441-554 (2 pis.). 



