32 MICROSCOPICAL DIAGNOSIS. 



with the blood. The specimen is then carefully warmed, and soon 

 the reddish-brown haemin crystals appear. To obtain a larger 

 number of cystals, a quantity of blood is boiled for one or two 

 minutes in twenty times its bulk of glacial acetic acid and immedi- 

 ately filtered. As the filtrate cools the cystals will be deposited. 

 To obtain crystals of haemoglobin, a drop of the blood of a rat is 

 mixed with two drops of water and allowed to evaporate slowly. 



CHANGES IN BLOOD. 



In 1881 Manassein made an extended series of observations 

 upon the changes which the red corpuscles undergo under various 

 circumstances. He made over 40,000 measurements of the corpus- 

 cles from 174 animals. The following results were obtained: 

 A reduction in the size of the red corpuscles was caused by septi- 

 caemic poisoning and probably traumatic fever, by an increase in the 

 bodily temperature, and by remaining a short time in a space sur- 

 changed with carbonic acid gas. An increase in their size was 

 caused by a reduction of the bodily temperature, by medium and 

 large doses of muriate of quinia, by cold, hydrocyanic acid in fatal 

 and non-fatal doses, muriate of morphia, oxygen, acute anaemia 

 (after arteriotomy), and by alcohol in intoxicating doses. 



Laschkewitsch found that the red corpuscles, in Addison's disease, 

 were larger, paler and altered in shape. Torueroth, Ilmoni and 

 others have reported the red corpuscles as wrinkled, crenated, and 

 shrunken in typhus and tabes. The sam^, has been observed in 

 Asiatic cholera, attributed to the reduction of serum. It has been 

 reported -that in the various peurperal disorders the rouleaux of 

 the red corpuscles is absent. 



EXCESS OF WHITE CORPUSCLES. 



We believe that this condition was first noticed by Professor 

 Virchow, in 1845. At that time he made a careful examination of 

 the body of a person whose death was not satisfactorily explained. 

 He found an enlarged liver and an enormous excess of white 

 corpuscles.' 



By preparing the blood in the usual way, and examining it with 

 a power of about 400 diameters, any great excess of the white cor- 

 puscles will be apparent, especially to one familiar with the appear- 

 ance of normal blood. This increase may be so great as to cause 

 one white to two red, in which case it will appear that the white 



