:318 Quant it at h^e Precipitin Tests 



the tube is drained as flir as possible by blowing out the moisture it 

 contains on to filter-paper, or it can be washed out and dried. The 

 mouth of the capillary is now brought in contact with the end of the 

 thermometer tube, which has been slightly raised at one end (A), and 

 fluid is allowed to pass into the capillary up to the pencil mark previously 

 noted. The amount of fluid which has passed into the capillary is now 

 read off on the scale. The thermometer tube is moved by means of the 

 handle (F) so as to prevent expansion of the fluid through the heat of 

 the hand. Where it is desired to know the actual quantity of pre- 

 cipitum, it is necessary to note the temperature and calculate accordingly. 

 This may be disregarded when a simple comparison is being made with 

 different quantities of precipitum in a given series, the measurements 

 being made in rapid succession under similar outward conditions. If it 

 is desired to make simply comparative measurements a diamond scratch 

 on any suitable tube is sufficient, only the measurements on the steel 

 scale being recorded." 



In the tables which follow the bloods are arranged in groups 

 according to the orders to which the animals yielding them belong. 

 In most instances the scientific names of the animals are given, this 

 is however omitted with the commoner domesticated or laboratory 

 animals. The numbers preceding the names of the animals refer to the 

 order in which they were collected by Nuttall and tested qualitatively, 

 as will be seen by reference to page 217. The date in the column 

 following is that on which the animal died, or on which its blood was 

 collected. The succeeding column gives the amount of precipitum 

 obtained with each blood tested. In all except the first series with 

 antihuman serum O'l c.c. of antiserum was added to 0"5 c.c. of 1 : 100 

 blood dilution. The percentages given in the last column are calcu- 

 lated upon the basis of the amount of precipitum obtained, the amount 

 given by an antiserum with its homologous blood dilution being taken 

 as 100 "/u- In most cases this figure has not been exceeded when the 

 antiserum acted upon a non-homologous blood, but notably in the case 

 of the anti-ungulate sera cases occur where non-homologous bloods give 

 higher figures. In some cases comments alongside the percentages 

 sufficiently account for high figures. Thus, the serum may have been 

 concentrated, or the precipitum loose in character, and consequently 

 with difficult}^ measureable. Brief comments in the text also serve to 

 explain and summarize the results. 



