CHAP. III.] THE BLOOD IN DISEASE. 



Besides the presence of spirillum, other changes have been noticed 

 in the blood in cases of relapsing fever, such as the disproportion 

 between white and red blood corpuscles and the presence of large 

 masses of protoplasm and of degenerated endothelial cells; these 

 changes are however found in many pathological conditions, especially 

 in fevers. 



Splenic Fever (of Cattle}. 



Splenic fever is a disease not uncommon amongst cattle, 



a ^ g us and is both enzootic and contagious, i.e. the disease occurs 



chiefly in certain districts where it is enzootic, but is also 



propagated by contact. In the blood of animals suffering from splenic 



disease, Davaine long ago found certain bacilli or rod-like bacteria, which 



he believed to be the cause of splenic fever. It was however found that, 



though inoculation with blood containing these bacilli produced splenic 



disease, the blood of the animals thus inoculated did not contain any 



bacilli, though highly active when inoculated. 



Koch 1 and after him Cossar-Ewart 2 have studied the life-history of 

 these organisms and have cleared up the discrepancy. Koch found that 

 in the blood and juices of the living body these rod-like bacteria multiply 

 by fission ; after the death of the animal, or when brought into cultivating 

 fluids, these rods grow into long filaments or threads which produce spores- 

 provided always the surrounding temperature remains moderately high ; 

 eventually the threads disappear and nothing but spores remains behind. 

 These spores, which withstand decomposition for a long time (while the 

 bacilli are very perishable), have been found to develop again into bacilli, 

 when in contact with the air and at a moderate temperature. 



The contagious character is due to the bacilli, but in the blood of the 

 slaughtered or dead animals the bacilli develop under favourable circum- 

 stances into spores, and these being much less perishable and easily wafted 

 about by currents of air are the cause of the epizootic character of the 

 disease. 



The observations on the presence of germs in the blood in other infectious 

 and contagious diseases have as yet led to no perfectly definite results, 

 though bacteria and micrococci have been seen in the blood in Pyaemia, 

 Septicaemia, Diphtheria and Scarlatina 3 . 



1 Cohn's Beitraye zur Biologie der Pftanzen, Band 1, Heft 3, p. 277. "Die Aetiologie 

 der Milzbrand-Krankheit, begriindet auf die Entwicklungsgeschichte des Bacillus An- 

 thracis." Cohn's Beitrcige zur Biologie der PJlanzen, Vol. n. 1876. 



2 Cossar-Ewart, "On the life-history of Bacillus Anthracis." Quarterly Journal of 

 Microscopic Science, Vol. xvm. (New Ser.), p. 161. 



3 While speaking of living organisms in the blood we may just mention the presence 

 of some more highly developed parasites found occasionally in the blood, thus: The Bil- 

 harzia Haematobia (Cobbold), or Distoma HaematoMum (Bilharz) inhabits the branches 

 of the portal system, but most commonly the small veins of the ureter, bladder and 

 pelvis of the kidney. It is endemic in Egypt where Griesmeyer found it in nearly 

 one-third of all autopsies. The full-grown animal, bisexual and belonging to the 

 trematodes, measures from 5 8 mm., and is soft-skinned. 



This disease is recognized during life by the presence of the characteristic ova and 

 embryos in the urine, which invariably also contains some blood. The eggs are 



G. 11 



