EXAMINATION OF COLOSTRUM 71 



two layers. Three c.c. of the supernatant fatty liquid are injected 

 into the peritoneal cavity of a guinea-pig. A similar quantity 

 of the deposit is treated in a like manner, and finally, two or 

 three other animals are inoculated intraperitoneally with the 

 semi-liquid substance obtained on mixing together the two layers 

 into which the butter has formed. At the end of expiration 

 of seventy days the animals which have not already succumbed 

 are killed, and a careful post - mortem examination is made. 

 Microscopic preparations and cultures are made from any organs 

 affected. The latter, taken together with the general aspect of 

 the lesions, will, in the majority of cases, be sufficient to enable 

 a diagnosis to be made between the true bacilli of tuberculosis, 

 and other acid-fast organisms resembling it. Bacilli which resist 

 in a moderate or somewhat feeble manner decolorisation by acids, 

 which develop rapidly at a temperature of t^j^ C, and grow 

 feebly at ordinary room temperature, which exhibit chromogenic 

 properties in culture, and give rise in the guinea-pig to lesions 

 which are not characteristically those of tuberculosis, must be 

 regarded as organisms of the acid-fast group, non-pathogenic for 

 man, though possibly related in some degree to the true bacillus 

 of tuberculosis {see also p. 253). 



Another method is that indicated by Roth. Five grammes of 

 butter are vigorously shaken up in sterile water, and the whole is 

 then centrifugalised. A fat-free deposit is thus obtained, and given 

 quantities of this are injected into animals in the ordinarj' manner. 



Special Methods 



Examination of colostrum — 



Colostrum is the term applied to the first milk yielded by the 

 cow after parturition. It differs considerably from ordinary milk 

 and generally appears as a thick, turbid, yellowish, viscid fluid. 

 When examined under the microscope it is found to contain, in 

 addition to the ordinary milk corpuscles, peculiar conglomera- 

 tions of very minute fat granules which are known as "colos- 

 trum corpuscles." The chief chemical differences between colos- 

 trum (or beastings) and milk are mainly three. First, colostrum 

 is deficient in casein. Secondly, it is proportionately rich in 

 albumen. Thirdly, it contains nearly three times more salts than 

 milk. Probably it is this excess of salts that usually causes it to 

 exert a purgative effect upon the new-born calf, and thus to remove 

 e meconium which has accumulated in the foetal intestine. 



