Tests loith Precipitins 383 



latter case taking place much more slowly and to a lesser degree than 

 in human blood. Bloods of different species of animals, dried on knives, 

 linen, etc., when dissolved in saline solution after 3 months, and cleared 

 by filtration, gave specific reactions. In making their tests they took 

 about 5 — 6 c.c. of salt solution for the solution of a dried blood drop of 

 about the size of a sixpence, adding about '5 c.c. of antiserum to 5 — 6 c.c. 

 of the blood dilution, the mixture being afterwards placed at 37° C. 

 Under these conditions marked reaction had taken place within 

 20 minutes. The lists of bloods tested by the above authors will be 

 found on page 162. 



Uhlenhuth (25. iv. '01) next reported that his anti-human serum had 

 served to identify human blood which had been dried 3 months. Six 

 samples of blood obtained from human cadavers and from healthy 

 persons, were allowed to putrefy, control tests being made with the 

 putrid bloods of the sheep, pig, horse, donkey, ox, cat, dog, goose, fowl, 

 hare, rabbit, deer. Solutions of these putrid bloods gave specific 

 reactions (see p. 119 et seq. also Plate and explanation at the end of 

 this section). All the bloods smelt of sulphuretted hydrogen, the 

 reaction being slightly alkaline. To obtain clear solutions, the bloods 

 were filtered through Berkefeld filters, the sterile filtrate being diluted. 

 A blood which had undergone putrefaction for 3 months still reacted 

 specifically to its antiserum. Faintly alkaline blood solutions con- 

 taining a small amount of soap, menstrual urine, human blood spots 

 on snow for two weeks (— 10° C), blood containing CO-haemoglobin, 

 albuminous, and especially pus-containing human urine, all reacted to 

 human antiserum, other bloods not doing so. 



Nuttall (11. V. '01), working independently, found antihuman serum 

 to cause specific precipitation in human blood which had undergone 

 putrefaction for 2 months. Bloods dried for 2 months and kept at room 

 temperature, or at 37° C. in the dark, and bloods exposed for a week in 

 the sun, gave specific reactions, as did also blister-fluid, nasal secretion 

 and human tears, the latter however to a slight degree only. On the 

 other hand, old horse serum (31 months in the laboratory, preserved 

 with trikresol) and human pleuritic exudate (6 months in the laboratory) 

 yielded effective antisera when injected into rabbits. He drew attention 

 to the reactions occurring in the bloods of allied animals which he had 

 tested. The allied species whose bloods reacted to antiserum for human 

 blood were man and 2 species of monkey, whilst ox and sheep bloods 

 reacted to both anti-ox and anti-sheep sera, the most marked reactions 

 being obtained when an antiserum acted upon its homologous blood. 



