COAGULATION OF BLOOD OF ARTHROPODS. 3! I 



(/) Collected in glycerine or in chloroform the blood coagu- 

 lates. 



(_/) The blood of the lobster collected in saturated urea solu- 

 tions or in a 25 per cent, peptone solution, forms a gelatinous 

 mass which does not contract in the usual way. Urea solutions 

 have a strongly dissolving influence on the blood corpuscles. 

 The shreds resulting from the first coagulation of the lobster 

 blood put into urea solutions, become transparent and swell ; in 

 glycerine they also become transparent but do not swell ; 

 returned into water they regain their usual characters. 



IV. Ox THE INFLUENCE OF MECHANICAL AGENCIES ON THE 



PROTOPLASM OF THE BLOOD CELUS OF SOME 



ARTHROPODS. 



It has been observed by previous investigators that the blood 

 cells may send out long processes which can adhere to solid 

 particles. It is however possible to produce a much greater 

 change. The protoplasm of a little clump of blood cells can be 

 transformed into a system of threads of different sizes. It is best 

 to use for such experiments cells which have been well preserved 

 and are somewhat swollen ; it is also necessary to use blood in 

 which it is possible to exclude the presence of an extra-cellular 

 mass of fibrin. Such cells are found, c. g., in blood collected in 

 gelatine solutions or in adrenalin or, also, iivhydrochinon. 



The necessary traction can be applied either by putting a 

 second slide on the first containing the blood in solution and 

 separating the two slides after they have been pressed together 

 or by whipping with a needle the blood cells on the slide. The 

 whole process can be followed under the microscope ; one can 

 see how cells arranged in a row become transformed into a 

 system of threads which no longer indicates that it is derived 

 from cells. Sometimes however we can see in the center of such 

 threads the nuclei of the cells, adapting themselves to the thick- 

 ness of the thread, or they may bulge out of the center of the 

 fiber as little spheres. Under such circumstances one single 

 cell can be changed into a very long thread. It can also be 

 seen that frequently spindle-shaped cells arrange themselves into 



