380 Vetermary Medicine. 



thaemia blood plates may be absent and in lymphatic leucocythae- 

 mia they may be in excess. 



Cafavy claims that many of the leucocytes have lost their ac- 

 tive amoeboid movements. 



Bright white crystals in the form of elongated octahedra are 

 found nor only in the blood but in the diseased glands, spleen or 

 marrow (Charcot's crystals). Clusters of discoid hsematoblasts 

 (blood plates) are present in the blood in variable numbers 

 (Schultze's granule masses). 



The bone marrow is marked by an accumulation of spheroidal 

 cells, which tend to pass into a condition of fatty degeneration. 

 Most of them are colorless, larger than the lymphocytes of normal 

 blood and have one large often vesicular nucleus, staining less 

 highly than the lymphocyte nuclei, and with neutrophile granules 

 in the protoplasm (myelocytes). There are besides, nucleated 

 red blood cells, spheroidal cells, containing red blood cells, and 

 Charcot's crystals. The marrow may be uniformly red, mottled 

 gray and red, gray, grayish yellow, or puriform (Delafield and 

 Prudden). This may affect one or many bones. The affected 

 spleen is usually much enlarged, at first uniformly, later uneven- 

 ly, firm or softened, and with thickened white capsule. The cut 

 surface is smooth, brownish red, or yellow, with white lines 

 (thickened trabeculae) and indistinct Malpighian corpuscles. It 

 contains glutin, glycocoll, hypoxanthin, zanthin, leucin, ty rosin, 

 and lactic, acetic, or formic acids. 



The affected lymph glands are somewhat enlarged, red or gray, 

 exceptionally, softened or caseated and otherwise contain an excess 

 of leucocytes. 



Slight haemorrhages may appear in any of these structures. 

 Lymphoid growths may appear in a number of other organs as 

 the liver, heart, lungs, kidneys, bowels, tonsils, the different 

 blood glands, the serosse and the retina. 



Genera affected. It has been seen mainly in dogs, but also in 

 horse, ox, pig, cat and mouse. Nocard has collected the follow- 

 ing cases : horse 9, cattle 6, pig 5, dog 22, cat i. 



Ivcisering found a horse's spleen weighing 2S kilogrammes. 

 Johne found a pig's spleen of 2.4 kilogrammes.. 



Causes. The primary causes of leukaemia are unknown. As in 

 anaemia all unhygienic conditions are invoked as causes. That 



