J.50 A MANUAL OF BACTERIOLOGY 



Strong, 1 in the Philippines, found that all vibrios which 

 agglutinated well with a cholera serum were genuine 

 cholera vibrios and that none of them was haemolytic. On 

 the other hand, Baerthlein 2 found that seven freshly 

 isolated strains of the cholera vibrio were definitely hsemo- 

 lytic in suspensions of sheep's corpuscles in from twenty- 

 four to forty-eight hours. Van Loghem 3 employs goat's 

 blood in haemolytic tests for the cholera vibrio. He 

 asserts that goat's blood is quickly haemolysed by haemo- 

 lyshig cholera-like (e.g. El Tor, p. 441) vibrios, but that 

 recently isolated cholera strains, if they haemolyse at all, do 

 not do so for some time twenty- four to forty- eight hours. 



With regard to this important question of haemolysis 

 and the cholera vibrios, Van Loghem 4 distinguishes two 

 types of blood solution, viz. haemolysis proper and haemo- 

 digestion. He asserts that the apparent haemolysis on 

 a blood- agar plate occasionally occurring with the true 

 cholera vibrio is really haemo- digestion. He distinguishes 

 the two conditions by the tint of the haemolytic zone 

 red in true haemolysis and greenish in haemo- digestion 

 and spectroscopically the affected zone shows oxyhae- 

 moglobin in haemolysis but not in haemo-digestion. The 

 blood agar used for the plates is composed of ordinary 

 nutrient agar with an addition of 11-12 per cent, of 

 defibrinated goat's blood. 



The cholera vibrio retains its vitality in cultures for a 

 month. It can multiply in water and on the surface of 

 moist linen, but rapidly dies on drying. Its thermal 

 death-point, according to Sternberg, is 52 C. with an 

 exposure of four minutes.; according to Kitasato, 55 C. 

 in about ten minutes. ' It is easily destroyed by the 

 ordinary germicides. 



1 Philippine Journ. of Science, vol. v, 1910, p. 403. 



2 Arb. aus dem kaiserl. Gesundheitsamte, xxxvi, 1911. 



3 Centr.f. Bakt., Abt. I (Originate), Ivii, 1911, p. 289. 



4 Ibid. Ixx, 1913, p. 70. 



