6H 



THK SPIKOCH.«TE OF EGYl'TIAN HEI.Al'SINCi FKVEU 



.Staining 

 reactions 



111 IJliiis stained \)\ [ji-isliiiiaii's niulliod the spirochiutes are found to vary in lengtli 

 from 13-5 /« to 22-5/1, wliile tlieir breadth is about 0'25 f. The number of spirals varies 

 from two to six, and the most characteristic feature of the parasites is the great irregularity 

 of these spirals and the marked tendency to the formation of loops, circles and {igure-of-8 

 forms (Fig. 25, a, h, c). A small and narrow spiral is frequently succeeded by a large and 

 wide one, so that there is nothing to be gained by measuring the individual spirals. So far 

 as this feature went there is a distinct resemlilance to i^pirochwla duttoni, and it is noticeable 

 in human, monkey and gerbil blood. For the most part the spirochictes stained uniformly. 

 Where breaks appeared in the ribbon they could usually be explained as divisions between 

 dividing forms. Parasites in gerbil's blood, however, tended to show unstained points 

 in the chromatin core (Fig. 25, c). This is also true to a lesser extent of those in monkeys 

 blood (Fig. 25, l>). In the light of the animal inoculations (ride infra), is it to be regarded 

 as an expression of the unsuitability of tlie medium to the spirochaete ? No evidence 

 of longitudinal division has been seen, and never more than two spirochsetes have been 

 found united end to end. Their ends are, as a rule, finely pointed. 



.\.\i>i.\L Inoculations 



I. Gekbils 



Loss of the 

 strain in 

 gerbils 



On January 12, 1910, a gerbil or desert mouse (GerbiUus pygargus), No. 1, was 

 inoculated subcutaneously with the blood of a patient which showed spirochsetes. On 

 January 14, this animal for the first time exhibited parasites in its peripheral blood, an 

 incubation period of two days. The spirochictes were fairly numerous but the animal 

 showed no sign of illness. A few drops of its blood were taken, citrated and inoculated 

 into gerbil 2. 



On January 15, spirochictes were still present in the blood of gerbil 1, but they were 

 absent on the 16th, and, despite daily examinations up to the 24th, and occasional 

 observations thereafter, they w-ere never again found. The gerbil at no time appeared ill. 



Gerbil 2. — Inoculated from gerbil 1, as stated, on January 14. Showed spirochtetes for 

 the first and only time on January 18. Never ill. 



Gerbil 3. — Inoculated from gerbil 2, on January 18. Showed spirochetes on January 20, 

 for the first and last time, but it was chloroformed on January 22, as it was looking ill and 

 its coat was rough. Some of its heart's blood was used for the inoculation of a monkey 

 (vide page 69) . 



Gerbil 4. — Inoculated from gerbil 3, on January 20, in order to preserve the strain. 

 A bacterial infection resulted, from which the animal speedily recovered, but, possibly as a 

 result of this accident, it at no time exhibited spirochictes. On January 24 it was 

 chloroformed and a few drops of its heart's blood were inocidated into gerbil 5. No 

 spirochaetes could be demonstrated in this heart's blood. Its liver and spleen examined by 

 the Levaditi method also failed to show spirochiEtes. 



Gerbil 5. — Inoculated, as just stated, with apparently sterile heart's blood from gerbil 4. 

 on January 24. It remained perfectly well and at no time exhibited a spirochaetal infection. 



Gei-bil 6. — Inoculated on January 18 with a few drops of citrated finger blood from a 

 patient in the non-febrile ulaije. It never showed spirochictes. 



From the above it will be seen that the strain in gerbils was unfortunately lost. 



