ON THE COAGULATION OF THE BLOOD OF SOME 

 ARTHROPODS AND ON THE INFLUENCE OF 

 PRESSURE AND TRACTION ON THE PRO- 

 TOPLASM OF THE BLOOD CELLS 

 OF ARTHROPODS. 1 



LEO LOEB. 



(From the Biological Laboratory, Woods Holl, Mass., and from the j. H. L. Molson 

 Laboratories of Pathology and Bacteriology, McGill University, Montreal. ) 



I. THE NORMAL COAGULATION OF THE BLOOD IN SOME 



ARTHROPODS. 



For this work the blood of Limulus polyplianus, Ho mams 

 Auicricaniis, Platyonychns occllatus, and some other arthropods, 

 was used. 



Coagulation of the blood takes place in a somewhat different 

 way in Linmlns, lobster and spider crab. 



In Linmlns the blood coagulates as a bulky mass which in 

 the following 24 hours contracts considerably. A second coagu- 

 lation of the fluid expressed from the clot may take place, to a 

 slight extent, forming very loose gelatinous masses around the 

 central clot, or more rarely, the whole serum may afterward 

 coagulate. 



In the lobster the first coagulum is usually relatively small, 

 consisting of shreds ; usually however, in the course of twenty 

 minutes to an hour, the serum remaining after the first coagula- 

 tion coagulates as a solid gelatinous mass which in the next 

 twenty-four hours retracts but little. Very rarely no coagulation 

 of the serum remains after the first coagulation takes place. 



In the spider or lady-crab, the first coagulation is similar 

 to that of the lobster blood. No second coagulation however 

 takes place. 



A combination of the following factors comes into play in 

 producing the clotting of blood in arthropods. 



1 This communication is in most parts only an abstract of a fuller report which 

 shall appear later. It is intended to continue these experiments. 



