The Origin of these Cells. 25 



late Dr. L. C. Wooldridge's now celebrated work on 

 " The Chemistry of the Blood," as peculiarly applicable 

 to this part of our subject. Speaking of the possible 

 origin of red blood corpuscles from plasma, he says : 

 " On the one hand the process is evidently allied to 

 crystallization, and the discs might be regarded as a 

 crystalline precipitate ; on the other hand, they may 

 be looked upon as imperfect cells. Omnis cellula e 

 cellula is a dogma. Is it true ? Are blood corpuscles 

 and plasma discs cells, or are they crystals ? Surely, 

 if ever we shall have a borderland between ' vital ' 

 processes and ordinary physical and chemical processes, 

 we shall find it in the blood plasma." 



These cells seem to arise from the molecular or nebu- 

 lous masses (of plasma) lying in the intervals of the red 

 corpuscles. This much is certain, that as they appear, 

 so does the nebulous matter disappear. They are at first 

 extremely transparent, and almost invisible, requiring 

 faith to believe in their presence. Twelve hours after 

 the bite, they may be readily seen. At this time, with- 

 out adding magenta, the macula is a bright particle on 

 the inner wall of the cell (not a pullulation). Twenty- 

 four hours after the bite, they are usually at their 

 greatest size, and the macula is small. When the cells 

 are smaller, the macula is always larger than when the 

 cells are distended. I have lately investigated this 

 point, and find it as it had originally seemed to me. 

 Should now magenta be added, and a 4 mm. apochro- 

 matic objective used, with a compensatory eye-piece, 

 the macula will be seen as a bright ruby-coloured 

 particle. The coloured macula can also be seen with 

 an ordinary achromatic object glass, but, necessarily, 

 its colour will not be so pure. 



