15 



în these cases there is a lack of acceptable 

 interpretatious, nor do we possess any facts 

 that can serve as a basis for hypotheses 

 that can explain that phenomenon. 



Although our experiments were perform- 

 ed on a large number of cases, we can 

 state nothing decisive in regard to the in- 

 fluence of atropine on the extrasystoles. We 

 can state nothing from the occurrence of 

 negative cases which indicate the absence 

 of any action of the remedy beside others 

 in which the rhythm was regulated. Further- 

 more, the inconstancy of extrasystolic beats 

 is well known, as they often disappear for 

 long perfods even in clinical cases in which 

 their frequence is greatest. 



Allorhythniias. 



In the tracings of the cardiac form of 

 the disease we have found anomalies of 

 rhythm that are repeated regularly and per- 

 iodically, thus giving uniform appearances 

 which can be grouped under the denomina- 

 tion of allorhythmias. Various factors enter 

 into their origin and hence the principal 

 interest is trying to recognize the conditions 

 that determine them. 



The most characteristic of such appear- 

 ances are the bigeminism and trigeminism 

 that may result in the same case or in dif- 

 ferent cases from differences of cardiac 

 rhythm, isolated or combined. 



The bigeminism usually results from 

 extrasystoles which are repeated in all the 

 cardiac cycles and the trigeminism from 

 two extrasystolic contractions; further, both 

 the appearances may depend upon altera- 

 tions of conductibility or upon these assoc- 

 iated with extrasystolic contractions. Only 

 the analysis of each tracing in concrete cases 

 can determine the relations between the 

 allorhythmia and the facts that cause it. 



Aside from these we have met other 

 appearances of allorhythmia in which the 

 irregularities are periodic and asssociated 

 with different conditions, such as auricular 

 fibrillation, and the interposition of extra- 

 systoles which succeed one another regu- 



larly. Such facts are exemplified in some of 

 our tracings and their semiology can there 

 easily be seen. 



The cardiac form of the disease being 

 thus described in its essential outlines, the 

 interest of this new chapter of human path- 

 ology is evident and the great pathologic 

 curiosity of the new trypanosomiasis in this 

 clinical phase becomes apparent. It is clear 

 that the subject is far from being exhausted 

 in this first summary description of the car- 

 diac form; there is much here for further 

 investigation in the interpretation of the 

 symptoms and for an exact knowledge of 

 other cardiac conditions of the disease. 



Aside from the present clinical obser- 

 vations the description here written is based 

 on the works of pathologic anatomy and 

 histology begun by the lamented Gaspar 

 Vîannaand completed by our eminent friend 

 Professor Bowman C. Croweli and our 

 companion Magarinos Torres. 



The clinical observations that have been 

 presented represent a small, selected, num- 

 ber of the large group of cases that have 

 been studied. However, by the uniformity 

 of the cardiac syrdrome made manifest by 

 them, they show the etiologic unity of the 

 morbid process localized in the cardiac 

 muscle. 



This condition of the disease, in which 

 cardiac symptor-is predominate over all 

 others, is generalized in the zones of endem- 

 ic trypanosomiasis, and it is there observ- 

 ed with a maximum intrnsity and exten- 

 sion, thus forming the clinical characteristic 

 par excellence of the American trypanoso- 

 miasis. 



The certainty of the etiology of all the 

 clinical obsevations here presented cannot 

 be contested, although in many of the pa- 

 tients neither the parasitologic diagnosis nor 

 the necroscopic proof has been made. 



In the cases in which necropsy was 

 possible, already a considerable number, the 

 symptomatology was well studied and was 

 in every point identical to those here report- 

 ed. This assures with absolute certainty 

 and irrefutable scientific precision the etio- 



