276 CYTODIAGNOSIS. 



It has been claimed that they contain glycogen by which means we can 

 distinguish them from endothelial cells which they so much resemble. 



Jousset introduced ionoscopy as a means of diagnosing tuberculo- 

 sis. The fluid was allowed to coagulate and was then digested with an 

 artificial gastric juice. The digested material was then centrifuged 

 and the sediment examined for tubercle bacilli. This process does not 

 seem to have met with much favor in this country. (Using sodium 

 citrate obviates the necessity for digesting the coagulum.) 



The same points will hold for ascitic fluid as for pleural fluid. 



In taking cerebrospinal fluid for culture and cytodiagnosis we use 

 a stout antitoxin needle without attaching a syringe. Aspiration is 

 responsible for many of the ill effects of lumbar puncture. The needle 

 should be about four inches long for an adult. Sterilize the skin and 

 needle as described for blood cultures from a vein. To make a 

 lumbar puncture, place patient on left side with knees drawn up. A 

 line at the level of the iliac crests passes between the third and fourth 

 lumbar vertebrae. Select a point midway between the spinous proc- 

 esses of these lumbar vertebrae and enter the needle 2/5 of an inch to 

 the right of this point, pushing the needle inward and upward. Collect 

 the material in a sterile test-tube. Make cultures on blood-serum and 

 then centrifugalize and examine the sediment as for pleural fluids. 



In general terms it may be stated that: 



1. A lymphocytosis indicates a tuberculous process. 



2. An abundance of polymorphonuclear and eosinophilic leuko- 

 cytes indicates a meningococcic or pneumococcic infection. 



A method of examination considered by neurologists as of differen- 

 tial diagnostic value is to count the number of cells in a cubic milli- 

 meter of the cerebrospinal fluid. The technic is to use a gentian-violet- 

 tinged 3% solution of acetic acid. This is drawn up to the mark 0.5, 

 and the cerebrospinal fluid is then sucked up to n. After mixing, the 

 cell count is made with the haemocytometer. Normally we have only 

 one or two cells per cubic millimeter, but in tabes or general paresis 

 this is increased to 50 or 100 cells. 



Trypanosomiasis gives a cellular increase very similar to syphilis. 



