128 



Dr. W. Stirling and A. Rannie. 



crenated and then to assume a globular form. This change to a 

 globular form occurred for the most part suddenly with a recoil or 

 jerk. At the same time processes were usually thrown out from the 

 corpuscles, sometimes to a considerable distance. Usually the cor- 

 puscle itself underwent considerable changes in shape. The nucleus 

 could not be seen. Small coloured droplets became extruded from 

 the corpuscle and danced over the field of the microscope with active 

 molecular movements. Sometimes the action of the reagent was less 

 vigorous — due to less being present — and then the corpuscles gra- 

 dually became globular, the sudden recoil not being observed. The 

 crenation was observed as before, and then the corpuscle began to 

 diminish in size, owing to the formation and detaching of its plastic 

 coloured substance. All the corpuscles ultimately become spherical 

 and very much lessened in bulk, and then gradually become de- 

 colorised. From some of those which had been of a globular form for 

 some time long delicate beaded processes were observed to pass. 



Kolliker* found that solutions of urea of 15 per cent, and upwards 

 produced similar changes in frog's blood. " The coloured blood- 

 corpuscles became gradually more jagged, and some became trans- 

 formed into the most beautiful stellate cells with at most three to six 

 tolerably long and more flask-like processes. The latter began as it 

 were to dissolve and disappear, partly by their margins being dissolved, 

 and partly by small coloured particles being detached from their surface. 

 These particles at once became pale and gradually disappeared. At 

 last there remained only the nucleus-containing portion of the cell, 

 as a small, round, dark red, refractive globule, which eventually became 

 pale, and which, even to the nucleus, disappeared without leaving a 

 trace behind." 



Preyer agrees that the above description is accurate, with the 

 exception of the part which refers to their becoming pale, which 

 Preyer ascribes to the action of water. Indeed, Preyer f obtained 

 similar results by allowing a drop of solution of urea to evaporate on a 

 slide and then placing a drop of blood upon the thin crystalline layer 

 of urea thus formed. The results he obtained are carefully figured, 

 and they agree exactly with the results we have obtained. 



The interest which attaches to the solvent action of urea is consider- 

 able, but the remarkable variety of shapes and the detaching of 

 droplets from the corpuscles are also interesting, more especially as 

 urea is only one of a number of reagents which cause a similar re- 

 action. 



We propose to continue our observations upon the effects of the 

 foregoing and other reagents upon human blood or mammalian blood 

 generally, which will form Part IT. 



* V. Siebold u. Kolliker's " Zeitsch. f. Wiss. Zoolog.," vol. vii, 1855, p. 183. 

 f " VirckoVs Archiv f . Path. Anat.," vol. xxx, p. 432. 



