122 THE BLOOD AND THE LYMPH 



found by Levinson to vary between P H 7.4 and 7.6, being therefore practi- 

 cally that of blood. On standing in unstoppered vessels the alkalinity 

 gradually increases so that P H of 8 may be reached in two hours. If the 

 vessel be tightly stoppered, however, P H may remain almost stationary. 

 The reason for this change is that there is as large a percentage of bicar- 

 bonate in the cerebrospinal fluid as in the blood plasma. The so-called 

 alkaline reserve, as determined by the Van Slyke method is therefore the 

 same as in blood plasma (viz., about 60). With regard to organic constit- 

 uents, there is only a trace of protein (0.02-0.04 total N.) but the urea 

 and sugar are present in about the same percentage amounts as in the 

 blood plasma. There is no certain evidence that any enzymes are con- 

 tained in the fluid. 



The pathological changes observed in the fluid are of two types, systemic 

 and meningitic. In connection with the former, it may be mentioned that 

 in uremia the amount of fluid is usually increased and there is a high per- 

 centage of urea; in diabetes, the sugar is increased; in the various psy- 

 choses, in epilepsy and chorea there may or may not be changes. In 

 hydrocephalus the amount of fluid is increased, but it is normal in its 

 properties. It is also, although less markedly the case, in encephalitis and 

 cerebral tumor. Regarding conditions in which the meninges are in- 

 flamed (tubercular, meningococcic, pneumococcic) the changes in the fluid 

 are very marked and of decided diagnostic value ; it is somewhat increased 

 in amount, turbid, forms a sediment, shows many cells, contains excess of 

 protein (globulin) and gives a typical culture of the infecting organism 

 when examined by bacteriological methods. Levinson has found that 

 there are significant changes in P H in various diseases and he considers 

 that several tests that have been devised for diagnostic purposes are in- 

 timately associated with the changes in P H . These tests are known as the 

 cataphoresis test, the colloidal gold reaction of Lange and the mastic reac- 

 tion, and they all depend on the manner in which the protein colloidal 

 particles aggregate or become precipitated. 



BLOOD AND LYMPH REFERENCES 

 (Monographs) 



iHowell, W. H.: The Harvey Lectures, J. B. Lippincott Co., xii, 272. 

 2Starling, E. H.: Human Physiology, Lea & Febiger, 1915. 

 sKowe, A. H.: Arch. Int. Med., 1917, xix, 354, 

 ^Williamson, C. S.: Arch. Int. Med., 1916, xviii, 505. 

 sTower and Herm: Proe. Soc. Biol. and Med., 1916, xviii, 505. 

 eTCous and Kobertson: Jour. Exp. Mod.. 1916, xxiii, 219, 239, 549. 

 TButler, G. G.: Quart. Jour. Med., 1912, vi, 145. 



SHowell, W. H.: cf. Harvey Lecture; also Am. Jour. Physiol., 1913, xxxii, 264. 

 Drinker, C. K., and K. K.: Am. Jour. Physiol., 1916, xli, 5. 



loDenny and Minot: Arch. Int. Med., 1916, xvii, 101; Am. Jour. Physiol., 1915, 

 xxxviii, 233. 



